The use of proxy votes in some Sinn Fein-dominated areas of Londonderry was more than 17 times the UK average at the general election.

Some of the largest Sinn Fein-represented wards had a proxy vote use more than 10 times the national average.

SDLP MLA Mark H Durkan met the PSNI this week to make a formal complaint about proxy vote abuse after the party lost its Foyle Westminster seat to Sinn Fein by just 169 votes.

Eamonn McCann, the former People Before Profit MLA, also made a complaint to the Electoral Office about proxy vote use in Foyle.

An analysis, using previously undisclosed proxy voting figures, shows the Brandywell area had a proxy voting record at this election of approximately 5.57%, 17.5 times the UK average of 0.32%.

Westland, also with a strong Sinn Fein majority, had a proxy vote record of 4.91%, 15.3 times the UK average.

Creggan South, one of the largest republican-leaning wards, had a proxy vote use 10.3 times the UK average.

This contrasts with the low use of proxy votes in unionist-dominated parts of the city, with a proxy rate of 0.33 in the Caw ward, approximately the same at the rest of the UK.

The Belfast Telegraph analysis comes from combining Election Office of Northern Ireland (EONI) proxy vote figures with UK averages held by the UK Election Commission.

According to Mr Durkan, the PSNI told the SDLP that it must provide evidence before it can act, as it does not want to be seen to be engaged in "political policing" against Sinn Fein. His uncle Mark Durkan lost his seat to Sinn Fein's Elisha McCallion in one of the closest results of the June 8 election.

The SDLP is now conducting a ward-by-ward analysis of the use of proxy votes. It said there was a disproportionate number of proxy votes among single and working mothers who agreed to give their vote to someone else, likely because of childcare duties.

One SDLP official involved in analysing the election result said he believed Sinn Fein registered its southern supporters Derry based on houses where there was an incongruous name in a one-family house. Many of these outside names then signed over their vote to a proxy, the SDLP claims.

"Certain names just spring out at you because they don't seem to belong in that house and then you look them up on Facebook and you find out who they really are," Mark H Durkan said.

Proxy votes are used in the UK when a voter nominates someone else to cast their ballot. It can be used for a variety of reasons, such as if the person is away, if they are working, if they are disabled or living overseas, according to the Election Commission.

All registered voters can be nominated as proxy voters for someone else and can be given multiple votes if the people they are replacing are close relatives.

Sinn Fein in Derry yesterday strongly denied any wrongdoing and said achieving an enfranchised voting system in the city had been a difficult struggle.

"Sinn Fein encourages people to exercise their right to vote, which was hard won in the north of Ireland," it said. "All political parties in the north encourage the electorate to utilise postal and proxy votes, where required, to ensure maximum participation in the democratic process." It repeated that proxy votes are a useful way for voters to be enfranchised. It said people should contact police if they know of voter fraud.

One Sinn Fein councillor in Derry suggested contacting the Sinn Fein press office when asked for a comment. Six other Sinn Fein city councillors were invited to comment. There is no suggestion of any wrongdoing on the part of any of the party's councillors, but there have been allegations of localised discrepancies in the use of proxy votes.

It emerged earlier this week that the number of proxy votes used in Northern Ireland has more than doubled in two years, predominantly in constituencies where Sinn Fein is strongest.

Sinn Fein won Westminster seats in seven of the eight constituencies where proxy votes had their highest use in Northern Ireland. The eighth constituency, North Belfast, saw a close run campaign between Sinn Fein and the DUP.

The overall use of proxy votes dropped in England and Wales between 2005 and 2010, said the Election Commission, but rose in Northern Ireland and, to a lesser extent, in Scotland.

Belfast Telegraph