It has been reported Leave.EU campaign backers frequently met officials from the Russian embassy.
Commenting, Peter Kyle MP, leading supporter of the People’s Vote campaign, said:
“These new allegations about contacts between one of the Leave campaigns and Russian officials only add to the feeling that the Brexit process is descending into chaos.
“Every day that passes sees new facts emerge, fresh promises broken and ministers and politicians in Westminster making more and more of a mess of Brexit. These latest allegations suggest some very shady dealings have taken place which should be properly investigated.
“But more importantly, this only emphasises the need for a People's Vote on the final Brexit deal, when we'll be able to see clearly the terms on which the Government is proposing to leave the EU and the country can decide whether or not those terms are good enough.”