As I was cycling along a quiet road, the sound of a vehicle close behind alerted me to danger. I glanced over my shoulder to see a white Transit van coming straight at me. Some split-second instinct made me veer to the gutter, but I still got side-swiped off my bicycle, narrowly escaping being crushed under the wheels.

Splayed on the pavement, cut, bruised and my heart pounding, I watched as the van sped off. 'Tatchell, you communist p**f!' a man shouted out the window.

Over the previous few months I'd been spat at, kicked, had dogs set on me and been attacked with cricket and baseball bats. I was terrified every time I stepped out of my flat. That incident was much worse — I knew I could have been killed. But as I picked myself up, I thought: 'I'm not going to let them beat me.'

It was 1983 and I was Labour's parliamentary candidate for Bermondsey, a deprived inner-city area of south London. Forty years have passed, almost to the day, since that infamous by-election on February 24 — but it is still regarded as the dirtiest, most violent and homophobic election since 1945.

Today, I am well known as a campaigner for human rights, but in the early 1980s, I was just a Labour Party activist with a day job in a centre for the homeless.

The by-election made me nationally famous — and the subject of what was later described as the most sustained vilification of a gay public figure since Oscar Wilde.

As a lightning rod for the vicious in-fighting in the Labour Party, I was cast as a dangerous radical because I challenged property speculators and advocated a national minimum wage.

My proposals for a negotiated peace settlement in Northern Ireland and laws to protect everyone against discrimination and LGBT+ equality are now mainstream: even the Conservatives agree with them. Back then, they were seen as extremist.

Almost no public figures were 'out' in that era and almost no candidates dared support LGBT+ rights. As an Australian-born gay social justice campaigner, I was denounced as a foreigner, immigrant, Marxist and pervert.

The bitter campaign saw homophobic anti-Tatchell graffiti daubed all over the constituency and more than 30 attacks on my flat, including two arson attempts — plus, a deluge of hate mail and a bullet posted through my letterbox in the dead of night.

All through that turbulent time, I was trying to sustain a passionate but secret relationship with the footballer Justin Fashanu. He was my comfort and support but we knew if we were discovered it would spell disaster.

Justin was the first black player to be transferred for £1 million, from Norwich to Nottingham Forest. In 1983, if he was known to be gay, his sporting career would be finished.

That may sound strange given the world we live in now, but it wasn't until 1990 that Justin felt able to come out. No other professional footballer would be open about their sexuality for 30 years.

So let me take you back to Britain — and Bermondsey — in 1983.

It was the year after the Falklands War and Margaret Thatcher was unassailable. Labour was in disarray with Michael Foot as leader and a Right-wing faction headed by David Owen and Shirley Williams having left to form the Social Democratic Party. Left and Right were battling for Labour's soul.

In Bermondsey, the far-Right British National Party was seeking a foothold. Skinheads were a familiar sight on the streets. The local football club, Millwall, was notorious for the violence of some of its shaven-headed fans. Perhaps not surprisingly, when I ran for election, four fascist and far-Right candidates stood against me.

I had arrived in London in 1971, aged 19 (I'm now 71). Seven years later, I struck lucky: I was offered a hard-to-let Greater London Council flat on the decrepit Rockingham estate. I'd seen some rough places but I was shocked when I got to Bermondsey. The once-thriving docks along the Thames that used to provide local employment had closed and the area had fallen into decay and decline.

It was a concrete jungle of brutalist housing blocks. They were rundown and neglected — despite being across the river from the riches of the City of London, the UK's financial hub. Some 90 per cent of homes were council housing, often poorly maintained with frequent long waits for repairs.

There was a lot of anger and no one was doing anything about it. The local Labour establishment, run by the long-standing MP Bob Mellish, and John O'Grady, the bullish leader of the local Southwark Council, was complacent and out of touch.

They were in thrall to get-rich-quick property developers. I could see the Bermondsey riverfront being seized for corporate headquarters and luxury apartments, with working class people shoved aside. I wanted to transform the area into an 'urban garden city' of parks, tree-lined streets and houses with gardens for local families.

So I brought together disaffected Labour members to resist the developers and reconnect the party with local trade unions, tenants' associations and community groups. Membership doubled to 800. I was elected secretary and became an unpaid organiser, devoting 40 hours a week and evenings and weekends to campaigning.

The Mellish/O'Grady faction denounced what I was doing as a 'palace revolution'. They weren't happy — though this hostility did not stop the secretly bisexual Mellish from trying to seduce me after his constituency advice surgeries at the local party offices.

When he made the first move on me I was shocked. This macho war veteran and son of a docker was the last person I would have guessed to be gay or bisexual. He was 67, I was 28. I didn't care about that, I just wasn't interested in him.

I gently declined his overtures. He was, obviously, a very sad and lonely man. I felt sorry for him.

When I courteously turned him down, he threatened me, saying: 'Don't ever mention this. No one will believe you. I'm a married man with kids, it will ruin your reputation, not mine.'

I assured him that I wouldn't go running to the Press to reveal his secret — and I didn't until after he died and was being extolled as a pious family man and an upholder of traditional Catholic values. In 1981, Mellish suddenly announced that he would not stand again as MP, so a replacement Labour candidate for Bermondsey had to be found. I was reluctant — I had no ambition to be an MP — but I had become the party members' favourite. I was selected, to the consternation of many Right-wing Labour MPs.

It was as all this was happening, that I met Justin in the London gay nightclub, Heaven.

We clicked immediately and began a relationship at a time when he was getting stick from his manager at Nottingham Forest, Brian Clough, who challenged him about going to what Clough called 'p**f clubs'.

Justin was very different to his public persona. He was nicknamed Flash Fash, but with me he was sweet, kind, homely and down to earth; the kind of boy-next-door any mother would love.

Occasionally, we'd go for cycle rides along the Thames, both wearing semi-disguises of baseball hats, sunglasses and scarves to avoid attention. When he stayed at my flat, he'd park his car some streets away, then walk to my block with a hood hiding his face.

My first-floor balcony had a low wall, so he'd crawl from the stairwell to my door, reckoning that even if someone spotted him coming into my block they wouldn't know which flat he went to.

Meanwhile, Mellish resigned as an MP to take up a lucrative job as vice chairman of the London Docklands Development Corporation, triggering the by-election.

I reckon I knocked on the doors of 23,000 voters in a bid to counter the vicious smears against me by the tabloid Press and rival candidates.

I hoped that if people met me they would realise that I was a decent bloke and not the far-Left gay monster that my critics claimed. It seemed to work: when the by-election campaign began, a Daily Mail poll said 47 per cent of people questioned intended to vote for me — more than double the number who planned to vote for any rival candidate.

Very reluctantly, I was pressured by Labour colleagues to come to an uneasy compromise about my sexuality — one I still regret today.

It was agreed that I would not discuss my sexuality with the Press. That's not because I was ashamed; it was because I didn't want gay rights to become the dominant election issue to the exclusion of my other policies, which would have happened in those days.

At this time, no parliamentary candidate from a national party had ever voluntarily come out.

If a reporter asked 'are you gay?' I wouldn't deny it. I simply said 'my personal life is not the issue'.

If it was raised on the doorsteps, though, I insisted I must be honest — and that not only resulted in a lot of violent assaults but it was used against me.

O'Grady stood as a rival Real Bermondsey Labour candidate and his supporters would say: 'Peter Tatchell admits he's gay. We can't have a man like that representing us in Parliament.' It was a deliberate appeal to homophobic voters.

I was shocked when Mellish chose to support O'Grady, given the latter's overtly anti-gay campaign. How could Bob Mellish, a bisexual man, do that?

Even more shocking was that supporters of my main rival, Simon Hughes, the Liberal Party candidate, also used my homosexuality to win bigoted votes.

Simon was bisexual, but closeted. No one suspected, but I'd had a tip-off from Liberal Party insiders who disliked the homophobic campaign that was being waged against me. Male canvassers for the Liberal Party went door to door wearing large lapel stickers saying, 'I've been kissed by Peter Tatchell'. Liberal election leaflets said it was a 'straight choice' between the two of us.

I could have outed Simon but I chose, on principle, not to do so. I did not want to stoop to those low tactics. Two decades later, Simon apologised. I accepted his apology. He claims he didn't know about the anti-gay tactics by his party and I have to accept his word, though I find it hard to believe.

During the campaign, an anonymous leaflet was put through people's letterboxes in the middle of the night. It featured pictures of me and the Queen, asking: 'Which queen will you vote for?' — adding, 'if you wish to question Mr Tatchell more closely about his views then why not phone him or visit him at his house' — giving my full home address and phone number. The result? I had more assaults and bricks and bottles thrown at my flat. The police refused me 24-hour protection.

So I boarded up the windows and moved everything flammable away from the front door and windows. I kept a fire extinguisher by the bed and installed a rope ladder so I could climb out the rear window in any emergency and shimmy down the side of my block of flats.

There were two arson attacks. In the first, petrol was poured through the letterbox, then set alight. The second time, petrol was poured through an air vent in the toilet.

I was lucky. Both times the fire burnt itself out because there was nothing much to burn.

I was very shaken to get up one morning and find a small envelope with my name, which had been posted through the letterbox during the night. When I opened it, there was a live bullet. I still don't know who sent it.

At times, it felt like living through a civil war. I began suffering from night terrors. I would relive being attacked and wake bolt upright in bed, with my heart pounding so hard I thought it would burst out of my chest.

It would take a good two hours to calm down and even think about going back to sleep.

Justin was horrified about what was happening. We were talking on the phone one evening and he said: 'I go to bed every night wondering whether you're going to be safe and alive the next day.'

On election night, though I knew support had been ebbing away and that Simon Hughes and the Liberals had been gaining ground, I was still under the impression that I would narrowly win.

But as the count proceeded and the piles of ballots stacked up, I knew I had lost.

It was a historic defeat: the swing from Labour to the Liberals remains the largest by-election shift in British political history.

It was gut-wrenching but I felt I had done my best in a situation of extreme adversity.

In my concession speech I urged my Labour supporters: 'Don't mourn, organise to win the coming general election.'

So I was still defiant, but I felt sad for the local Labour activists who had stuck by me. It was their loss, too.

After the election was over, the extreme homophobia I encountered prompted me to put more energy into campaigning for LGBT+ rights.

A sad postscript to this story is that my relationship with Justin began to fade a few months after the election, but we remained good friends.

When I heard he had committed suicide in 1998, I was heartbroken. I wish he would have phoned me when he was suicidal. Perhaps I could have given him the support and strength to keep living.

After the madness of Bermondsey, there was a great groundswell of public revulsion about the way I'd been treated, which helped to make it easier for subsequent gay candidates. When the Labour MP Chris Smith came out in 1984 — just a year later — there was no outcry and that's partly because people were horrified and ashamed by what was done to me.

I still get occasional panic attacks. Many of my teeth were chipped and cracked due to assaults but, luckily, the dental hospital has reconstructed them.

I'm glad that my campaigning has helped change social attitudes so that parliamentary candidates today don't have to go through the violent and homophobic horrors that I experienced back in 1983.

n The Bermondsey by-election features in the documentary Hating Peter Tatchell, out now on Netflix.