Andy Burnham was under mounting pressure to break his silence on immigration last night as it emerged more than 500 small-boat migrants arrived in his first week.

Sources said one dinghy was a staggering 12m long and carried 165, with the six vessels crossing the Channel in total this week branded ‘Burnham’s boats’.

And more migrants were spotted in the Channel yesterday, meaning the tally was on course to hit around 600 overnight.

Embarrassingly for the new Prime Minister, the Home Office data was published while he was unveiling his No10 North ‘gimmick’ 300 miles away in Manchester.

Critics said Andy Burnham should spend more time trying to stop the boats and blasted him for failing to once mention immigration in his first week as PM. This is despite the issue topping a string of recent voter polls.

He has so far talked about lowering bills and bus fares, and launched his No10 North yesterday – hailing it the ‘best day of my life’. 

But the public remains in the dark about his plans to secure Britain’s borders. 

Reform UK Leader Nigel Farage said: ‘“Open borders Burnham” will do nothing to stop the illegal and dangerous invasion of our country, he won’t even mention it. Only Reform will stop the boats.’

The Tories’ shadow home secretary Chris Philp said: ‘More illegal immigrants crossed the Channel under Keir Starmer than under any other prime minister.

‘And now we’ve had a terrible start with Burnham’s boats and the largest ever migrant dinghy crossing yesterday with 165 illegal immigrants on it. Only the Conservative Party have a plan to end Channel crossings by leaving the ECHR [European Convention on Human Rights] and deporting all illegal immigrants within a week of arrival.’

Labour peer Lord Glasman, founder of the Blue Labour Right-leaning group, called on Mr Burnham to take a more ‘aggressive’ stance on the Channel crisis.

He said: ‘What’s happening here is absolutely outrageous. I’ve been in favour for a long time of putting the Royal Navy in the Channel and literally stopping the boats... we’ve got to have a much more aggressive policy towards the French government.’ The arrivals came after figures showed small-boat migrants accounted for just 7 per cent of deportations last year, suggesting most are not deported.

Wednesday’s tally of 172 migrants came on three boats, as did Thursday’s total of 366. That means on Thursday, a staggering average of 122 people were packed on each of the three vessels. But Home Office sources said 165 were on board just one, smashing the previous record of 128.

More than 77,000 migrants have arrived in the UK after crossing the Channel since Labour’s election victory in July 2024.

Since records began in 2018, more than 200,000 have arrived.

While the number of arrivals so far this year – more than 13,000 – is over 40 per cent down on last year, experts believe crossings could go up again. Wednesday’s crossings were the first recorded since July 10, which experts said was partly because of windy weather and choppier waters.

A Home Office spokesman said: ‘Removals of small-boat migrants are at record levels and asylum claims down by 12 per cent.’