Seven times as many migrants from the poorest countries in Europe registered to work in Britain after immigration rules were relaxed last year.

Official figures showed 187,370 Romanians and Bulgarians were given National Insurance numbers over the course of 2014, up from 27,700 during the previous year.

This represented a 576 per cent increase in the numbers of migrants from the two most deprived countries in the European Union who registered to work or receive state benefits in the space of just 12 months.

Romanians and Bulgarians now make up a quarter of all new NI numbers allocated to foreigners, the Department for Work and Pensions said.

Experts said the figures suggested that many of these immigrants had been in Britain for months or even years, working illegally “in the shadows”.

Jobs that pay “cash-in-hand”, such as construction or cleaning, will have enabled them to support themselves while not paying full taxes, it was claimed.

The figures prompted warnings that the sudden increase in the number of eastern Europeans registering for work could make it harder for British people to find jobs.

A National Insurance number is a legal requirement for anyone wanting to work as an employee, or to claim state benefits and tax credits.

The dramatic rise followed the lifting of restrictions on the kinds of work Romanians and Bulgarians could do in the UK, a controversial change which took effect on January 1, 2014.

Under “transitional” rules introduced when Romania and Bulgaria joined the EU in 2007, migrants from these two countries could only work in the UK in seasonal jobs such as fruit picking, or if they were self-employed.

These restrictions ended on January 1 last year and all Romanians and Bulgarians were then given the same rights to work in the UK as British citizens.

MPs and academics said that the “huge” rise in NI numbers issued last year showed Britain’s borders had not been properly controlled.

Experts at Oxford University said many Romanians and Bulgarians may have moved to Britain while the restrictions were still in place and claimed they were self-employed but were in fact working as employees on building projects or in other “cash-in-hand” jobs, without formal contracts.

Then, once the restrictions were lifted last year, they registered for NI numbers so they could work legally as employees.

Carlos Vargas-Silva, an economist at Oxford’s Migration Observatory, said: “These figures give the impression that many of these people were here already doing something but we don’t know what that something was. There is a possibility that many of these people were in that informal economy without the proper permits to work.”

Keith Vaz, chairman of Parliament’s Home Affairs Select Committee, said the “huge” rise showed migrants who were already working had “come out of the shadows” when the restrictions were lifted.

“It is clear that the 1st January last year provided people with the opportunity for the first time of working legally. Romanians and Bulgarians who were working in the black market and in the shadows had to obtain National Insurance numbers in order to become employees,” he said.

“There is still a massive problem in tracking and monitoring people who come over.”

Nigel Mills, the Conservative MP for Amber Valley who led a campaign to extend the employment restrictions on Romanians and Bulgarians, said voters feared a sudden increase in legally registered workers would make it harder for British people to find employment.

“Nobody objects to having people come here when we need the skills. But equally we can’t just have unlimited numbers of unskilled people turning up looking for work. We have still got a lot of people out there who need jobs. It’s not sustainable,” he said.

Source: The Telegraph