Cambridgeshire Police Chief Constable Julie Spence complains the force can't cope

A chief constable gave a stark public warning yesterday of 'immense' pressure placed on resources by the unprecedented influx of immigrants.

Julie Spence, who heads Cambridgeshire Police, took the highly unusual step of singling out Poles, Lithuanians and Iraqi Kurds who are carrying knives on the streets.

The comments of such a senior officer in an Parliamentary evidence session will spark widespread alarm at a time when the UK is struggling to control knife crime.

Mrs Spence said: 'We have had the Iraqi Kurds who carry knives and the Poles and the Lithuanians who carry knives. If it is normal to carry them where you come from, you need to educate them pretty quickly. We have done a lot of work to tell them not to, and we have seen it go down.'

The chief constable  -  who first sparked a nationwide debate on migrant crime last year  -  also said there were problems related to violent debt recovery among Eastern Europeans.

'There is an assaults pattern going on in relation to debt recovery. There is an issue of confidence in the police.'

Mrs Spence also described as 'very worrying' growing labour and sexual exploitation within former Communist communities whose nations have joined the EU since 2004. In the same evidence session, Local Government Association chairman Sir Simon Milton reported a series of 'spikes' in crime as a result of mass immigration.

He told the Home Affairs Select Committee there had been an issue with largely Romanian pick-pocketing gangs in the Westminster area.

'Nationally there has been no crime wave but there are instances where there have been spikes in certain types of criminal activity. Much of it is low-level  -  driving offences, and so on.'

Mrs Spence has given previous warnings of the link between migrants and certain types of crime. Last September she highlighted a surge in drinkdriving, for example, by migrants with 'different' cultures and standards.

But it is highly unusual for a police chief to single out certain nationalities as posing a specific crime problem.

Simply carrying a knife in public is a criminal offence, punishable by up to four years in jail.

Mrs Spence, however, is establishing a reputation as an officer prepared to confront uncomfortable truths.

Shocking: MPs today heard that a large number of immigrants are carrying knives

Addressing the Police Federation Conference last month, she warned that the economic downturn could spark tensions among ethnic groups.

Violence has already erupted between immigrant populations in the past. And she warned that the looming financial crisis could trigger unrest as competition for jobs increases. She also claimed that the Government had greatly underestimated the soaring numbers of Eastern Europeans entering the UK.

Mrs Spence said as many as 1.4million had arrived since the borders were opened to them four years ago  -  half a million more than the official figure.

She called for a European-wide police database so officers can easily check whether immigrants they arrest have any previous convictions in their home country. Mrs Spence cited one example of a violent Polish man arrested by her officers who came up as clear on the police national computer. They contacted the Polish authorities and had to wait 24 hours to find out he was a convicted murderer.

Shadow Home Secretary David Davis said last night: 'Under Labour, fatal stabbings are up by almost a third and the Government's lax approach means people carry knives in the street with impunity. We need more effective action to tackle knife possession  -  regardless of who is carrying them.

'This means taking a zero-tolerance approach  -  including action to confiscate such weapons and punish those carrying them. Only this will send a clear message that we are serious about tackling a problem, which one senior judge has labelled an epidemic.'

A Home Office spokesman said: 'The vast majority of foreign nationals entering or living in the UK play by our rules. However, we will not accommodate those that abuse our hospitality by becoming involved in crime.

'In 2007 we removed over one person every eight minutes, including the highest-ever number of foreign lawbreakers, up by a huge 80 per cent to 4,200.

'The new UK Border Agency has put in place a national network of crime partnerships so that we stand shoulder to shoulder with police forces and systematically target foreign lawbreakers for expulsion from Britain.'