Conservative MP Philip Hollobone has said one of the key reasons Romanians should be prevented from moving to the UK because of the number that commit crimes.
"There is currently a crime wave of bag snatchers and pickpockets on London underground," he said. "Eight out of 10 pickpockets on the London underground are Romanian."
The Kettering MP, who is a special constable, made the comments during a parliamentary debate on Romanian and Bulgarian immigration on Monday evening that had been triggered by people signing an e-petition on the subject.
He told MPs that it was not racist to be opposed to immigration but rather a recognition that "our country is full and we will not put up with it for too much longer".
"For all of us who are concerned about immigration, it has never been about the colour of somebody’s skin or about the culture or country they come from," he said. "It has always been just about the numbers."
"Our country is one of the most crowded in the world, and we simply cannot cope with another large-scale wave of immigration into this country, especially from countries with which we have very little in common, such as Romania and Bulgaria."
On Tuesday afternoon the Romanian and Bulgarian ambassadors to London will give evidence to the home affairs committee on EU migration.
From next year their citizens will be granted the same freedom to move and work in in the UK as all other EU nationals.
The government has refused to speculate on how many people will choose to move to the UK once the transitional controls that were placed on EU-wide movement are lifted.
The Romanian prime minister, Victor Ponta, told BBC Newsnight last night that "nothing significant is going to change regarding Romanian migration to the UK" from next year.
"The biggest wave of Romanian migration has already been during 2007-2008 and the main destination was Spain and Italy," he said.
He added: "There is no danger or wave of immigrants coming from Bulgaria or Romania."
And on Sunday Bulgaria's ambassador accused Ukip's Nigel Farage's of engaging in "hostile propaganda" against his people.
"There were, for instance, pre-election leaflets in counties that say the Bulgarians will be a threat to social system of the UK. This is absolutely unacceptable in a European country," he said.
Farage said the pressure on housing, education and services from immigration "poses a major problem" especially if people from other countries claim benefits.