The Home Office spent a record £5.38bn over the last year on asylum - more than a third higher than the previous year.
Figures released on Thursday showed spending on asylum rose by £1.43bn in the 2023/24 financial year to £5.38bn - 36% higher than in 2022/24 when £3.95bn was spent.
The latest figure, covering the Conservatives' final year in government, is the highest amount since comparable data began in 2010/11.
It is more than four times the equivalent figure for 2020/21 (£1.34bn) and nearly 12 times the total a decade ago in 2013/14 when it was £450m.
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New data has also found the number of asylum claimants living in hotels has increased since Labour came into power in July.
The Home Office costs cover all its spending on asylum, including direct cash support and accommodation for asylum seekers, plus wider staffing and other related migration and border activity.
It does not include the cost of operations responding to Channel crossings and intercepting migrants as they make the journey to the UK.
However, the data suggests most migrants entering the UK on small boats do then end up in the asylum system.
Since Labour came into power, 19,988 people have crossed the Channel on small boats to get to the UK illegally.
The latest asylum spending data is from when the Conservatives were in power and comes as further data revealed net migration to the UK fell by 20% in the year to June 2024 from a record 906,000 the year before.
The Office for National Statistics (ONS) found net migration - the difference been people immigrating and emigrating - stands at an estimated 728,000.
Sir Keir Starmer said his party had inherited an "utter mess" from the Tories as he accused them of reforming policies to "liberalise immigration" and having "lost control of the borders".
He said the government was "taking a different approach" by cracking down on any abuse of visa routes, setting out a plan to reduce immigration and "smash the gangs" taking people across the Channel.
The prime minister said the cost of processing asylum claims needs to be brought down, as does the use of hotels.
He said the government has redeployed 1,000 Home Office staff to process asylum claims, and said his government has returned 9,600 asylum seekers since July.
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Number of asylum seekers in hotels soars
New Home Office data has also revealed 106,181 asylum claimants were in accommodation at the end of September. That is an increase of 9,539 from May this year.
Of those 106,181 asylum seekers, 35,651 were being housed temporarily in hotels due to lack of other accommodation at the end of September, up by 6,066 from 29,585 at the end of June.
It is the first quarterly rise for a year, although the figure is still some way below the recent peak of 56,042 at the end of September 2023.
Labour promised to close asylum hotels in their manifesto, but border security minister Dame Angela Eagle last week said more asylum hotels have opened since the party came into power.
She told parliament there are currently 220 hotels in use for asylum seekers, with seven having shut since July - but 14 more have opened.
Dame Angela said the reason was the situation left by the Conservatives, with 116,000 asylum seekers "stuck in a backlog" of more than two years when Labour came into power in July.
She said the system "ground to a standstill" because the Tories were busy pursuing the Rwanda policy "which was doomed to failure".
The minister said Labour did not commit "to close all asylum hotels within four months".
(c) Sky News 2024: Home Office spent record £5.38bn on asylum over past year