London - Passengers on the London Underground subway network do not just have each other for company on the daily commute: they are also sharing seats with more than three million bugs, research claimed on Monday.

A study by the capital's Evening Standard newspaper suggested the average underground train or bus seat could be home to up to 70 different types of bacteria, including tuberculosis, cold and flu viruses.

But although one specialist called for anti-bacterial gloves and wipes to be made available to reduce infections, another played down fears that travelling on the Tube could pose health risks.

The findings emerged after Evening Standard reporters took swab samples from each of the London Underground and bus routes for testing for a range of nasties.

Only the north-south Victoria subway line passed the hygiene test while the Piccadilly line - which runs out to London Heathrow airport - was found to relatively clean, recording about 200 000 bacteria on seats.

London Imperial College scientist Peter Openshaw, who specialises in viral infections and respiratory diseases, told the newspaper there was a "very real risk" of coughs and sneezes passing on infection on public transport.

"If someone sneezes, wipes their hand across their nose and then holds on to a rail, the chances are the next person's hand will become infected," he added.

But biologist Liz Sockett, from Nottingham University, central England, argued that not all bacteria found in seats was likely to be harmful.

"This is around the level you would actually find in a bed and it's not all 'nasty' bacteria," she said.

As London Underground bosses said they were hoping to up cleaning of seat covers in the future, commuters still faced potential pitfalls in the office.

New Scientist magazine recently published evidence suggesting the average workplace has 400 times more bacteria than a toilet seat.