Boris Johnson is being asked to secure the safe return of a British woman who claims her father has locked her up in Saudi Arabia.

Amina Al-Jeffery was supposed to have returned to Britain by 4pm on September 11, in line with a High Court order passed last month, but has yet to do so.

Mr Justice Holman at the Family Division of the High Court ordered Saudi academic Mohammed Al-Jeffery to "permit and facilitate" the return of his daughter to England or Wales.

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Geraint Davies, the MP for Swansea West, has since written to the Foreign Secretary asking what he intends to do, saying Mr Johnson is "directly responsible for her freedom and safety".

"She is a 22-year-old British citizen who has said she has been held against her will," the Labour MP said in the letter.

"Therefore, for you as Foreign Secretary to fail to secure her safe return would be a dereliction of your duty."

Miss Al-Jeffery - who grew up in Swansea and has dual British and Saudi Arabian nationality - complained her father locked her up in his flat in Jeddah because she had ''kissed a guy''.

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She had described herself as being ''locked in a cage''. But her father disputed the allegations and said he was trying to protect her.

At the public court hearing in August, Mr Justice Holman concluded that Miss Al-Jeffery's freedom of movement had been severely constrained.

Mr Davies added: "I appreciate Amina's father may try to make some implausible suggestion that Amina no longer wants to return and that you may wish to acquiesce this absurdity to avoid embarrassing the Saudi authorities.

"However, claims made under duress should be rejected. If Amina is in the captivity of her father then he may compel her to make statements by email, text message or telephone from captivity."

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The Labour MP said only when Amina is returned to the UK, in an environment free from coercion and once she is judged to be mentally fit, can her decision to stay in Saudi be "reliably be believed".

A Foreign and Commonwealth Office spokesman said: "We are in contact with Ms Al-Jeffery and are ready to provide her with assistance if needed. We will also remain in contact with her legal team and Saudi authorities."