A transsexual killer who pushed his cross-dressing friend to her death under the wheels of a Tube train has been jailed for life with a minimum tariff of seven years.

Senthooran Kanagasingham, 35, pushed friend Sonia Burgess into the path of a train at King’s Cross St Pancras Tube station on October 25 last year.

Ms Burgess, 63, a divorced father-of-three cross-dressed who was content to remain biologically male, died instantly.

She worked professionally as David Burgess for law firm Luqmani Thompson and Partners in High Road, Wood Green. The firm said the highly respected human rights lawyer led “genuinely trailblazing” legal test cases.

Last Friday Kanagasingham, who is also known as Nina, was cleared of murder but jailed after admitting manslaughter on the grounds of diminished responsibility.

The Sri Lankan, of Chichele Road, Cricklewood, had been taking hormone therapy to change his gender at the time of the killing and was also taking anti-depressants.

Kanagasingham had known Ms Burgess for several years after the pair met in a London club and he had been visiting her flat each week to have a shower and talk about his problems.

But he was “highly psychotic” at the time of the killing and also believed his victim was plotting to kill him.

The court heard the paranoid schizophrenic had become angry after Ms Burgess told Nina’s GP he was becoming “anxious and stressed” at an appointment earlier that day.

Prosecutor Brian Altman QC said the killing had been executed with “full force” and “perfect timing”, telling jurors: “The witnesses variously describe the push as very hard, full force, executed with perfect timing and with, as some witnesses say, both hands in the middle of the back.”

Judge Stephen Kramer said he was worried Kanagasingham would pose a threat to those he befriended in future.

He added: “There is a significant risk that your mental condition might deteriorate. I make it clear that you will not be automatically released.”