A senior SNP councillor in Glasgow has quit the party after claiming he was gagged over concerns he raised about the governance of a local food bank.

Billy McAllister, who made his name as a politician who challenged organised crime in the city, said the party leadership in the city is “intolerant” of free speech.

He also said the SNP is becoming like Scottish Labour and said he is “very sad” to resign.

However, a party spokesperson said the councillor had been given a "final written warning" over his "behaviour toward colleagues".

A member of the SNP for over 20 years, McAllister was elected in 2006 as the councillor for Milton after a by-election and rose to become the party’s deputy leader on the local authority.

During his successful election campaign, Nicola Sturgeon said: “Billy has a great track record in helping the local community as an activist, but he will be able to do so much more as a councillor. I want him as part of the SNP team in the city chambers that stands up for our communities against Labour misrule.”

He launched high-profile campaigns and was vocal in calling for a crime family to be evicted from the council-funded Chirnsyde community centre in his area.

However, he also had well-documented difficulties, such as being fined £200 in 2014 after swearing and acting in an aggressive manner towards a man in Glasgow.

McAllister was also reported to the fiscal after a spat with community activist Graham Campbell, the partner of SNP MP Anne McLaughlin, but the case was dropped.

One of his latest campaigns was to voice concerns about the running of the Greater Maryhill Foodbank, an issue that has contributed to his decision to resign.

The foodbank has links to SNP figures in the city and McAllister said he was blocked from talking about the matter by the party leadership on the council last year.

“A gagging order was put on me,” he said. “They told me to sign it, otherwise I would be out of the party. It was quite an ultimatum.”

McAllister accused the party in Glasgow of double-standards: “When I was fighting Chirnsyde, it was Labour…The SNP encouraged me, but when I am trying to do the same thing on the foodbank issue, I am told to remain silent.

“My own experience is that the SNP is intolerant of free speech…I have been punished for whistleblowing.”

He also said he feared the SNP could end up like the party it has replaced: “It’s like the three monkeys: hear no evil, see no evil, speak no evil. If you don’t address these issues, and you don’t take action, then they will end up like Labour. That’s a fact.”

On Susan Aitken, the leader of the SNP group on the council, he said: “She’s been a total nightmare...She has given me no support whatsoever.”

He added: “She rules with an iron fist. That’s part of the problem.”

McAllister said of the general style of the SNP leadership on the council: “It’s turning into something that I’m not wanting to be part of.

“They are just power mad. They are getting carried away and don’t want to live in the real world.”

He added: “I have sent a letter of resignation to SNP chief executive Peter Murrell.

“I am very sad to have to take a decision like this, but they leave me no option. They have backed me into a corner.”

An SNP spokesperson said: "Following a final written warning over his behaviour toward colleagues, Billy McAllister has chosen not to play a constructive part in the SNP group. The SNP group will continue to focus on holding Labour to account in the City Chambers and setting out our plans for a stronger and more prosperous Glasgow at next year's council elections."

On the foodbank issue, the spokesperson said: "SNP councillors representing the area have been in regular contact with volunteers, council officials and the police to support the foodbank."