Channel 4’s documentary The Romanians Are Coming has sparked a diplomatic row, with the Romanian embassy expressing its “bitterness and disappointment” over the programme.

Ion Jinga, the Romanian ambassador in London, has written to the producers of the three-part series accusing them of reinforcing negative stereotypes. Meanwhile three members of the Romanian parliament have written to the British ambassador in Bucharest to claim that the channel was inciting hatred and discrimination.

The MPs’ letter, seen by the Observer, adds: “We kindly ask you to consider what your reaction would be if TVR, the Romanian public television channel, would launch a campaign of denigration pointed towards the British citizens in our country, generalising cases of alcoholism and paedophilia displayed by some British citizens (cases we are sure you are aware of), and turning them into the general image of all British citizens in Romania. The documentary broadcast by Channel 4 does the exact same thing.”

Channel 4 says the series – which ended on Tuesday – explored the lives of Romanians trying to make a new life in Britain, and sought the truth behind the headlines about immigration.

The first programme featured Alex, who lived in a car park next to Victoria station in London, and a Romany man who struggled to settle in Liverpool.

The second and third episodes also examined the poverty of Romania, where the richest 10% would be among the poorest 10% in the UK. The narrator says: “When you live in a place as poor as this, then where can you find hope?” One immigrant coming to the UK says to camera: “I am sure the English will throw us a rope.”

A review in this newspaper described the programme as “an intelligent programme likely to dispel prejudices”, and it has been widely applauded for its humanity. However the response from some Romanians in the UK has been far less complimentary, with a silent protest recently held by students outside C4’s offices.

The ambassador complained that the programme has “ignored the fact that, in their overwhelming majority, Romanians living in Britain are well integrated into the local society”. He further claims that there are more than 4,000 Romanian doctors and nurses in Britain.

Immigration is likely to be one of the major issues during the general election campaign.

Last week an analysis from Oxford University reported that the migrant population of England had risen by 565,000 since 2011, with two-thirds coming from the EU.

The figures suggest the foreign-born population of every local authority in the country may have risen.

The Migration Observatory unit said it came up with the projections because similar official data will not be available before the general election.

On 1 January 2014, Bulgarians and Romanians gained the same rights to work in the UK as other EU citizens.

A spokesman for C4 said: “This sensitively handled series confronts, head on, many of the stereotypes and widely held prejudices about Romanians coming to the UK by providing an honest account of the experience of different individuals attempting to make a life in Britain.

“The series makes it clear, throughout, that the majority of Romanians in the UK are professionals with guaranteed jobs who pay their taxes and contribute to the British economy.”