A record number of people were granted British citizenship
A record 164,635 people were granted British citizenship last year, government figures have shown.
Almost one third of the new citizens were from Africa, and 22% were Asian.
The Tories expressed concern at the figures, saying "the public will be alarmed that passports are being handed out at such a rate."
Separate Home Office figures showed the number of asylum applications in the first three months of 2008 rose 16% on the same period last year to 6,595.
Indians topped the nationalities receiving citizenships at 14,490, followed by Filipinos (10,840), Afghans (10,555), South Africans (8,150) and Pakistanis (8,140).
Afghans were the fastest-growing group with a 211% rise on the previous year.
Shadow immigration minister Damian Green said: "Given the government's ineptitude, how can they guarantee [passports] are being granted to suitable people? This shows why it is essential our border controls are tightened."
There has been another drop in the numbers of migrants registering their arrival from eastern Europe.
In the 2008 first quarter, 45,000 registered to work, down 7,000 on the same period last year.
The figures also showed that the number of asylum applications was rising after an record low was reported last year, but the 2008 figure is still the second lowest since 1993/94.
In 2007/088 most of those seeking asylum were from Afghanistan, Iraq, Zimbabwe or China.
The number of failed asylum seekers deported from January to March was down 13%, to 2,805.
The total number of people removed - including foreign criminals - was up 12% to 16,760.
The figures showed Britain received the largest number of asylum applications in Europe in the first three months of this year.
There were 7,700 including dependants, compared with 7,400 to the second most popular country, France.
"People in Britain welcome legal migrants who work hard and play by the rules," Immigration Minister Liam Byrne said.
"But we will not tolerate law breakers, which is why we will prioritise their expulsion from Britain."
A separate set of figures from the Office of National Statistics has suggested record numbers of people are leaving the UK to live abroad, but more are arriving.
The population and migration figures for 2006 estimated 400,000 people had left Britain while 591,000 had come in, with the biggest group of entrants being British. Polish citizens were in second place with some 68,000 arriving.