Trawlermen who sailed up the Thames in a pro-Brexit demonstration could send an angry armada to the UK Parliament amid fears the fleet has been “betrayed” by the prime minister.

The Fishing for Leave campaign represented skippers and crews across the country during the EU referendum campaign and were joined by Ukip leader Nigel Farage on a 30-vessel flotilla to London.

They even clashed with charity campaigner and former Boomtown Rat Bob Geldof on the Thames.

But now they have warned Theresa May’s flagship speech on Brexit did not offer a strong enough stance to protect the fishing rights of British vessels.

And the group is considering fresh action to ensure their industry is given an exemption to escape a repeat of the controversial Common Fisheries Policy (CFP).

When the UK negotiated its way into the European Common Market in 1973 then-prime minister Ted Heath was accused of “selling out” the fleet.

Since then, the CFP has given EU member states equal access to each other’s waters, allowing foreign vessels to fish around the Scottish coast.

Last night, skipper Alan Hastings, spokesman for Fishing for Leave, said his colleagues were “spooked” by Mrs May making no mention of British fishing in her speech.

He said: “Although a small industry, it is one the government could utilise to show its resolve on taking back control of our borders and ending the authority of EU law.

“Therefore, why not mention what could be a beacon for Brexit?”

The lobbyists are calling for the CFP to be scrapped altogether, rather than being adopted into UK law and then later repealed as has been proposed.

A recent report from the group estimated scrapping the CFP could be worth £6.3billion to the UK economy and sustain tens of thousands of new jobs.

Mr Hastings warned there may be a repeat of the flotilla demonstration or other “publicity stunts” if the government does not protect UK fleets.

The Ayrshire skipper added: “There’s something fishy going on down in London at the moment.”

Liberal Democrat MSP Tavish Scott has also warned the government that Scotland’s fishing communities “know their history”.

The Shetland MSP said: “They have been on the end of politics for decades.

“Edward Heath’s Tory government traded the industry away in the 1970s when Britain joined the common market.

“Is history about to repeat itself? Theresa May’s Brexit speech this week set out her negotiating position as the UK leaves the EU.

“In a little-reported passage, she cited industries who would want a good deal for the UK. German exporters, French farmers and Spanish fishermen.”

Mr Scott said Mrs May’s throwaway concession to Spanish skippers would open the door to fleets from around the continent.

He added: “That does not sound a good deal for the Scottish fishing industry. Are the Tories about to sell us out again?”

However, another prominent pro-Brexit skipper, Peterhead’s Jimmy Buchan, urged caution from his colleagues.

The former Conservative candidate for Westminster, who was part of the flotilla, said: “The detail hasn’t been negotiated yet.

“What she did say is that the European migrant workforce who work in our fish processing will be protected.”

When the Fishing for Leave flotilla sailed to Westminster in June they were broadsided by Bob Geldof who was pictured holding two fingers up towards Mr Farage.

In the wake of the clash Mr Geldof was accused of attempting to “torpedo” the event but a spokesman for the singer said it was important someone made a “counter-argument”.

Last night a UK Government spokeswoman said: “We recognise the importance of our fishing industry and we will be working hard to secure the best possible deal for all our fishermen – both now, and for the future.

“Leaving the EU is a real opportunity to review fisheries management in order to ensure fair access to quota, sustainable stocks and a healthy marine environment.”