Nigel Farage has issued a huge warning to the UK after "Rejoiner" Sir Keir Starmer's Brussels visit.

The leader of Reform UK said the "most alarming thing" about the Prime Minister's address to European Union leaders on Monday night was Sir Keir's push to "deepen" industrial collaboration.

He said: "The most alarming thing to come out of last night was an agreement to deepen industrial collaboration. So does that mean we're joining part of EU industrial policy? Does it mean in terms of defence we're joining their procurement programme? There's still a lot of unanswered questions, but I didn't like the language at all.

"The very fact he was there discussing such things shows our prime minister is a Rejoiner at heart."

When it was pointed out that Sir Keir is simply fulfilling a manifesto pledge to improve Britain's trade and investment relationship with the bloc, Mr Farage said: "Well, yes, but, you know, if that means signing up to EU programmes that certainly wasn't explicit in the manifesto.

"There's a lot more detail that we need to find out, but I found the symbolism of it a bit disturbing."

Sir Keir told European Union counterparts there should be increased military co-operation and greater industrial collaboration to strengthen defence on the continent.

The PM addressed EU leaders over dinner in Brussels where he became the first British prime minister to attend a European Council meeting since Brexit.

Mr Starmer, who is pushing for closer defence and security ties as part of his "reset" in relations with the EU, also called for more work on military research and development, where the UK has "unique skills". He also suggested measures to improve military mobility and logistics.

On the impact of Brexit on trade, Mr Farage admitted many businesses in the UK have seen red tape get worse, but balked at the idea of giving EU fishers greater accesss to British seas in return for closer ties.

He told the BBC: "I do not see that any steps back towards a failing European Union make sense in a world that is changing very quickly."

Mr Farage added: "You can have negotiations. You can be friendly. You can do all those things. But if we start to tie ourselves to industrial collaboration, as appears was agreed last night, then we find ourselves with less flexibility in doing deals with countries like America."

On polling that shows a majority of Brits want closer ties to the EU rather than the US, Mr Farage said the EU is "diminishing" every year, adding: "My fear is we tie ourselves to EU law, that we start to accept single market regulations."

He said instead the Government can do a free trade deal with the US as well as other countries around the world, but would also need to address Britain's "desperate" lack of productivity to turn the economy round.

The Department for Business and Trade has been approached for comment.