Airlines should be forced by a change in the law to provide two inches more leg room on board passenger jets, a cross-party committee of peers said in a report on air travel.
The Lords committee on science and technology accused the Civil Aviation Authority (CAA) of ignoring its own research which recommended the regulatory minimum distance between seats should be increased to 28.2ins (71.6cm) or ideally to 29.4ins from a current minimum of 26ins.
The lack of leg room for seating in passenger jets has been linked to scares over deep vein thrombosis (DVT) which can cause fatal blood clots, particularly on long-haul flights. The research also showed more space between seats could allow passengers to evacuate planes more safely in an emergency.
CAA-funded research has revealed a study on the room required for passengers to adopt the 'safe brace' position might have suggested the minimum distance between seats should be increased up to 35ins.
"We find it astonishing the CAA has chosen to ignore this piece of research and its recommendations to implement their own research," said the report.
The committee added: "While most UK airlines currently operate with a 30in or above seat pitch, the committee feels this should be guaranteed by the CAA. The fact that many airlines already provide this suggests a regulatory requirement would not place onerous demands on the industry." The peers also criticised the Government for increasing the tax on airlines who have been attracting passengers with long legs by offering premium economy seats on long haul flights. The roomier economy seats which made travel more comfortable for taller passengers were taxed at the higher rate of air passenger duty for business and first class tickets which was doubled in February to 80.
They said the tax on such premium economy seats should be cut to the standard rate of 40.
"Given that the premium economy seating appears to be one way in which airlines are catering for the health requirements of taller passengers, premium economy should be taxed at the standard rate of air passenger duty," said the Lords committee.
There should also be further research into possible links between contaminated-air incidents on planes and long-term ill-health, the committee said.
The report also said they were "very concerned" to hear from unions that fatigue in pilots could be putting lives at risk.
The peers recommended the CAA should work with the aviation industry to ensure pilots got proper rest periods. The report was a follow-up to the committee's air travel and health report on the risks of on air travellers.
A CAA spokesman said: "Any move to increase the minimum seat pitch will have to be taken on a European-wide basis by the European Aviation Safety Agency (EASA).
"The current requirements are determined on safety grounds to ensure that passengers have enough space to evacuate an aircraft in an emergency, and not for health or comfort grounds. Most UK airlines already offer a 28-inch minimum seat pitch."