The Liberal Democrats would seek to invest an additional £500m a year in mental health services if they formed part of another government, HSJ can reveal.

Deputy prime minister Nick Clegg has said in an exclusive piece for HSJ today that he wants “at least half” of his promised £1bn real terms NHS funding increases between 2016 and 2018 to be spent on mental health.

The money would help in “completing the journey” to make “parity of esteem” for mental health services a reality, he said.

“To fund this we’ve identified three tax changes that will, together, deliver an extra £1bn for the NHS, and I want at least half of that for mental health,” Mr Clegg wrote.

“This is a top priority for me and my party. To make that clear, I will ensure this mental health commitment is on the front page of our manifesto.

Nick Clegg

Mental health services are a ‘top priority’ for the Lib Dems, says Nick Clegg

“[It will be] a priority not just for the election but for any government of which Liberal Democrats form part.”

The party has said it would, in government, make £1bn real terms increases in the NHS budget in 2016-17 and 2017-18.

An HSJ investigation earlier this year found the 57 mental health trusts had seen their total income reduce in real terms by £253m between 2011-12 and 2013-14, as well as reductions in beds, nurses and doctors.

Mr Clegg is also set today to announce at the Liberal Democrat Party conference an extra £120m funding for mental health services across 2014-15 and 2015-16, and the introduction of waiting time standards for the sector.

His piece for HSJ wrote: “For too long, mental health has been a ‘Cinderella’ service. Forgotten, neglected, underfunded, stigmatised.

“In the last four years, Liberal Democrats have been working hard to put that right: writing parity of esteem into law for the first time, improving crisis care, extending access to psychological therapies.

“But the more we try to do, the clearer it becomes that a small, short term effort is not sufficient. Mental health services have been so neglected it will take at least another parliament to make equal standards a reality.”