Labour peer Lord Greville Janner, whose Hampstead home was searched by police over allegations of child sex offences, will not be prosecuted due to the “severity of his dementia”.

Today, the Crown Prosecution Service announced it would not be prosecuting the 86-year-old in relation to accusations he abused children in Leicestershire children’s homes in the 1970s and ‘80s because he is suffering from Alzheimer’s disease.

In a statement, director of public prosecutions Alison Saunders said: “The CPS considers that in the light of the medical evidence Lord Janner would inevitably be found not fit to plead, not fit to instruct his legal team and not fit to challenge or give evidence in a trial.

“That means that a criminal trial, to determine whether or not he was guilty of any offence, could not now properly take place.”

In December 2013, Leicestershire Police officers searched a luxury flat belonging to Lord Janner in West Heath Road, as part of a probe into historic child sex offences alleged to have taken place in the Leicestershire area..

Lord Janner, a former Labour MP representing Leicester North West and then Leicester West for 27 years, was made a life peer on his retirement from parliament in 1997 as Baron Janner of Braunstone, in Leicestershire.

The father-of-three, whose wife of more than 40 years died in 1996, became a barrister in 1954 and was appointed a QC in 1971.

He is associated with a number of Jewish organisations having served as president of the Board of Deputies of British Jews from 1978 to 1984.

Lord Janner is described on his website as “a key international figure in efforts to seek compensation and restitution for Holocaust victims”.