A woman threw messages in bottles from a high-rise window after her boyfriend held her captive and assaulted her.

John Lawson attacked Klaudia Budzinska after she tried to walk out of Lawson's flat in Lansdowne Court, Dundee.

He dragged her back in before "detaining her against her will" and locking her in the flat.

Lawson then pinned Ms Budzinska down and choked her so viciously she could not breathe or speak.

He then fell asleep, leaving Ms Budzinska locked in and unable to escape.

She first tried to hang a knotted bed sheet out of a window in a bid to climb down but dropped it five floors to the ground when she realised how far she would fall.

She then wrote a note and put it in a bottle and threw it towards a passer-by who did not see it and walked on.

A second note was then thrown towards a man walking towards his granddaughter's house nearby.

He spotted it and looked up to see Ms Budzinska standing on a balcony - where she made a "be quiet" gesture before putting her hands together in a praying motion then running her finger across her throat.

The note read: "Call police, he almost killed me. Don't buzz or knock. Kick the door in. Pls help."

Lawson, 35, a prisoner at HMP Perth, pleaded guilty at Dundee Sheriff Court to abduction and behaving in a threatening and abusive manner.

Sheriff Alastair Brown deferred sentence until next month for social work background reports.

He said: "Compressing the neck and restricting her breathing is exceptionally serious."

Lawson was remanded in custody.