George Osborne takes a swipe at Theresa May over Brexit and her immigration policy

LONDON - George Osborne appeared to take a swipe at Prime Minister Theresa May over her contribution to the Remain campaign in the run-up to June's European Union referendum.

Speaking on the BBC's The Andrew Marr Show on Sunday, the former chancellor of the exchequer said he was initially opposed to a referendum on Britain's EU membership but "was not going to sit it out" despite his reservations.

It appeared to be a thinly-veiled dig at May, who unlike Osborne and her predecessor David Cameron was not exactly a prominent Remain campaigner in the run-up the referendum, despite endorsing Britain staying in the EU.

Osborne, now a Tory backbencher, made 230 media appearances in the final six weeks before June 23, according to research published by the University of Loughborough. In comparison, May made just 29.

Interestingly, the number of media appearances May made for the Remain campaign was well short of that of Jeremy Corbyn, who made 123 in the same time frame. But it was the Labour leader who came under attack by many of his own MPs for not being enthusiastic enough in his support for Remain, while May managed to evade criticism.

Osborne unleashes more criticism on May

The MP for Tatton also criticised the prime minister's plans to include international students in net immigration calculations.

Last week the Guardian revealed that May was considering plans to cut the number of visas granted to international students applying to study in the UK by nearly 50%, despite protests from cabinet ministers like Boris Johnson.

Osborne told Marr that such proposals were "not sensible" and risked threatening one of the country's biggest exports to the world.

"Students who turn up, they're only here for two or three years, and education is one of Britain's biggest exports," the former Chancellor said.

"I think it's one of Britain's biggest successes in the world and creates links of affection for Britain. When I was the chancellor I thought it was not sensible to include them in the figures."

There has been tension between Osborne and May since the day the latter became prime minister back in July.

Friends of Osborne said the MP was "furious" after media reports claimed he had been sacked by May as part of her cabinet reshuffle because it was actually him who made the first move by submitting his resignation.

"If that is how Mrs May wants to stamp her authority, then so be it," an unnamed friend of Osborne told The Times.

"She has every right to pick her own football team. But she has a majority of 12 and no room to make enemies. The shabby way they [Osborne and others] have been treated suggests she's already made a few."

In the same interview with Marr, Osborne admitted that the Remain campaign suffered from a lack of "optimism" and "authenticity" and should have put forward a more positive case for remaining part of the 28-nation bloc.