Heathrow travel care wants to provide a fully comprehensive seven-day 24-hour service. It is open for six days between 9am and 5pm with an out-of-hours emergency number.
Its pounds 74,000 funding comes primarily from BAA, British Airways and Hillingdon council. KLM, the Dutch airline, has agreed to contribute pounds 1,000 a year and agency managers have asked the other 96 airlines using Heathrow to follow suit.
Fear of flying is one of the biggest problems faced by some travellers.
'We get people creating mayhem at the gate and swearing at people,' says Bob Mannear, the agency's deputy manager. It often becomes clear they are terrified of getting on their plane and are subconsciously trying to avoid leaving terra firma.
It is not just passengers who benefit from the service. Staff at the airport also have access to counselling services, for anything from relationship problems to post-traumatic stress, which is still suffered by some staff who flew to Scotland to sift through the wreckage of the Lockerbie flight for bodies.
Bank holiday weekend has been busier than usual. An Egyptian language student arrived at Heathrow to discover his flight was from Stansted; another didn't have the money for the bus fare to Salisbury; and a deaf woman had turned up to collect her daughter but didn't even know the flight number, time of arrival, or where the plane was coming from.
Another woman with a heart problem came back from holiday, but spent
hours at the wrong terminal after missing the driver her tour operator had arranged. Earlier, staff had dealt with a Briton who arrived homeless and penniless after being deported from a Canadian jail.
Some find the whole airport experience so alien they suffer a breakdown. One middle-aged business man, travelling first class from India to New York via Heathrow, lost his wallet. 'He suddenly felt
he had lost his complete
identity, explains Mr Mannear. 'He was shaking and couldn't even remember his phone number. Everything had gone completely.' Gradually staff got him to remember who he was, what was in the wallet, and numbers to call.
Travel care has regular calls from the Foreign Office, when Britons are deported from other countries.
One man, who had been born in Britain but moved to America with his parents at the age of three, turned up completely disorientated at the agency after being deported by US authorities following a short prison sentence.
Although he had always considered himself an American, he had never taken up citizenship and found himself on a plane to London, leaving his wife and children behind.
Sometimes people are deported after suffering mental health problems abroad. Travel care staff will meet them off the plane and make an assessment of what care they need.
But the agency also bails people out when they arrive at Heathrow without money for the Tube. 'They can take the pounds 2.50 and go, or sit and talk.
'Quite often people spend two to three hours here and look at quite difficult things in their life. When you are in crisis, with proper help, that can be an important period of growth.'