The survey by the Joseph Rowntree Charitable Trust (JRCT) revealed that there were 331 destitute asylum seekers on the streets of Leeds, West Yorkshire - an increase from 118 in 2006.

A trust spokesman said this was just a sample of the tens of thousands of asylum seekers, refused asylum seekers and refugees now living destitute in the UK.

The More Destitution in Leeds report, which follows a survey carried out in the same city 18 months ago, found that asylum seekers were forced into poverty without access to health care and education or permission to work.

The number of children recorded as destitute in Leeds has increased almost fourfold from 13 to 51, the trust said.

There was also a steep rise in the number of destitute Zimbabweans from four in 2006 to 56 this year. Zimbabweans are now the single biggest national group of destitute asylum seekers in Leeds, forming 21% of the total, while Iranians are the second biggest with 16%.

Bill Kilgallon, a commissioner in the original JRCT inquiry, said the Government's asylum policy was having a "devastating impact" on people in "desperate need of help".

He said: "This survey clearly shows that the asylum crisis highlighted 18 months ago is actually getting worse despite - and, in some cases, because of - the introduction of the Government's New Asylum Model. The scale of overall destitution has almost tripled, more children are suffering and more people are suffering for longer. This cannot go on."

The trust found that the most common reason for people becoming destitute was a delay in Section 4 support, which is available to asylum seekers or refused asylum seekers who are unable to return to their country of origin or who have been given leave to seek a judicial review.

The JRCT called for urgent Government action to improve the asylum process and provide interim support arrangements in case of delays in Section 4 payments. Ministers should also provide more support for local agencies and the voluntary sector to help those who are in need of assistance, the trust said.