A new Mental Health Bill is facing mounting criticism from a group of MPs over its definition of mental disorder, which they say is putting those not regarded as mentally ill at risk.

By broadening the definition of disorder, the bill would target individuals on grounds of sexual orientations or sexual identities.

This effectively means people with unusual fetishes or wanting gender reassignment surgery are likely to face discrimination and possible detention in a mental institution.

Based on legal advice, the joint Human Rights Committee of MPs argues the proposed bill raises significant human rights issues, and is urging the government to redefine its terms with further information and explanation.

The 12-member group has strongly condemned the bill as discriminatory, and warn that people who are not considered to be mentally ill could be covered by it.

The proposed new law says any individual could be detained on grounds of unsoundness of mind.

The committee argues that anyone with Gender Identity Dysphoria or extreme fetishism could be targeted, even though the individuals concerned does not suffer from any actual mental disorder.

Transexuals are not within the scope of the proposed new law.

The committee wants an end to compulsory treatments for all patients with mental health problems, and instead make it a necessity only if they are of therapeutic benefits to the individuals concerned.

The MPs also propose extra safeguards to protect patients who are force-fed, kept in seclusion or given electro-convulsive therapy.

The Mental Health Bill has already proved to be deeply unpopular in the House of Lords, where peers from all parties have thrown out a clause which proposed the resignation of a member of parliament who has mental health problems.

A survey carried out in 2005 by the charity Together found that up to 60 MPs admitted to suffering from a mental breakdown.