A retiring Labour MP is threatening to sue her own party after it chose a male Sikh candidate to replace her instead of another woman.

Slough MP Fiona Mactaggart accused Labour chiefs of flouting party rules that say a female candidate must succeed a woman MP who steps down.

The local party has instead chosen Tanmanjeet (Tan) Dhesi, 38, who will become the first turban-wearing Sikh MP if he wins on June 8.

The local party has chosen Tanmanjeet Dhesi, 38, to replace the retiring MP who will become the first turban-wearing Sikh MP if he wins on June 8

Former Home Office Minister Ms Mactaggart, 63, one of the richest MPs, reportedly wanted the seat to go to Jayne Lim, a doctor and vice-chairman of campaign group Chinese For Labour.

The Mail on Sunday has been told that Ms Mactaggart threatened Labour’s ruling National Executive Committee with legal action over the matter.

According to one source, she said she could stand against Mr Dhesi as an independent.

That could split the Labour vote and hand the seat, won by Ms Mactaggart with a 7,336 majority in 2015, to the Tories. Mr Dhesi was born and bred in Slough but is a former mayor of Gravesham in Kent.

Ms Mactaggart, a former councillor and a primary school teacher, entered the Commons as a ‘Blair Babe’ in Labour’s 1997 landslide

On Thursday he was elected as a Labour county councillor in Gravesend. Nearly one in ten people who live in Slough is Sikh. Labour officials defended Mr Dhesi’s selection in Slough, claiming that exceptions can be made to the party’s all-women shortlists rule to accommodate ethnic minority candidates.

Ms Mactaggart reportedly told the NEC in a leaked email that she could seek a judicial review in the courts.

Labour leaders were said to be stunned by her actions.

Mr Dhesi launched his Election campaign yesterday at the party’s local HQ in Slough.

Last night, Ms Mactaggart declined to comment. A Labour spokesman said: ‘The NEC considered the best applicants for each seat, including the requirement to select more women and people from black and minority ethnic communities.

‘In the 13 seats where Labour MPs have stood down, the party had chosen ten women and three people from ethnic minorities to ensure Labour MPs better reflect the communities they serve.’

Ms Mactaggart, a former councillor and a primary school teacher, entered the Commons as a ‘Blair Babe’ in Labour’s 1997 landslide.

She rose to become a junior minister in the Home Office between 2003 and 2006.

She decided to quit the Commons after the General Election was called, saying that she was ‘bored by the political squabbles over personalities’ and that she no longer ‘possessed the passion which has driven my politics’.

She was one of 13 MPs who voted against the snap Election.

In recent years there have been a number of Sikh MPs, including Parmjit Dhanda in Gloucester. However, he and others did not wear a turban.