An LGBT campaigner in Brighton, who is fighting to have his criminal conviction for being gay overturned, has received a letter of gratitude from the Prime Minister.

George Montague, 91, is a regular fixture of Brighton Pride. Each year he attends the event, driving his mobility scooter with the banner: “I’m the Oldest Gay in the Village.”

Mr Montague was convicted under Britain’s former anti-gay laws during his mid-40s.

Simon Kirby, the Conservative MP for Brighton Kemptown, has asked for the Ministry of Justice’s help to overturn the conviction.

In May 2012, a law allowing men to apply for historic consensual convictions for same-sex activity to be erased from police records came into force.

Mr Montague, who was a senior scout commissioner working with disabled children at the time of his conviction, says he is also owed an apology from the Scouting movement for ejecting him.

The Argus reports he said: “I was in the Scout movement for 40 years. I ended up with a conviction and I feel upset and angry. The police were institutionally homophobic at that time and I want an apology from the Scout Association.

“I wrote to the Prime Minister thanking him for getting the gay marriage law passed. I thought it would never go through.

“I was very pleased to receive a personal letter in reply from the Prime Minister.”

In his reply to the campaigner, David Cameron wrote: “I understand that you have been involved in Gay Pride events for some years, and were at Pride in London this year, as well as being elected an Ambassador for Brighton Pride 2013.

“Let me congratulate you for this, and your involvement in charity fundraising. Your commitment to the community is very impressive.”

This year, Mr Montague is once again a Brighton Pride Ambassador.

He will be signing copies of his book ‘The Oldest Gay in the Village’ in the Access Tent in Preston Park from 2pm-4pm and at Gelateria De Luca ice-cream parlour in St James’ Street from 6pm-8pm on Saturday.

Mr Montague first came to Brighton in the 1950s to explore the gay scene and 11 years ago bought a home in the city.

He realised he was gay in his twenties – long before the decriminalisation of homosexuality.

Like many of his friends at the time, Mr Montague married his wife, Vera, at the age of 37, and the couple had three children.

They were together for more than 20 years.

In 1997 he met his partner Somchai Phukkhlai in London. They entered into a civil partnership in 2006.

Earlier this week, David Cameron gave his backing to this weekend’s Brighton Pride in a statement of support.

Labour leader Ed Miliband recorded a video for the festival, along with Green MP Caroline Lucas.