A total 37,562 asylum applications were made in the year to September, an 18 per cent increase on the previous year.
It comes after 27 migrants drowned in the Channel when their overcrowded dinghy sunk on Wednesday.
More than 25,700 people have made the dangerous crossing from France to the UK by boat so far this year - three times the total for the whole of 2020.
A Government spokesperson said the figures “demonstrate the complex scale of the global migration crisis” and that Thursday’s tragedy “serves as the starkest possible reminder” of the dangers of the crossing.
Net migration, separate to asylum claims or refugees, fell last year due to Brexit and Covid restrictions.
The difference between people entering and leaving the UK was 34,000 in 2020 compared to 271,000 the previous year, according to the Office for National Statistics (ONS).
Despite this, there was “no evidence of an exodus” after Britain’s break off from the European Union, the ONS stressed.
The figures mark the lowest level of net migration for many years but statisticians said it was “difficult to disentangle” the fallout from the end of free movement and the pandemic.
Backlog of asylum cases
The backlog of asylum cases waiting to be dealt with is also at a record high with 67,547 pending an initial decision, according to new figures from the Home Office.
Applications had fallen “substantially” during the initial coronavirus outbreak but are now higher than pre pandemic levels, it said.
This increase is likely linked to the easing of Covid travel restrictions and small boats arriving to the UK, it added.
The University of Oxford’s Migration Observatory said the sharp increase in Channel crossings was a “key factor in pushing up the number of asylum applications in the third quarter of 2021”.
Applications were up 75 per cent in July to September compared with the same period last year.
Some 15,104 claims were opened in just three months which is the highest on record since 2003.
The highest record for quarterly applications is 22,760 in October to December 2002 which was “partly driven by military action, conflict or political unrest in countries such as Iraq, Afghanistan, Zimbabwe and Somalia”.
Last week, one of the Government’s immigration ministers told MPs that migrants boarding small boats to get to the UK is becoming the “route of choice for facilitations by evil criminal gangs”.