Howard Slater was once a professor of microbiology. Now he is boss of Frog Tours in London.

What the hell's that?

It's a Frog Tours bus - an amphibious vehicle that travels around London and then goes into the Thames. It's based on the DUKW landing craft, designed and developed to facilitate European landings in the second world war.

Where did you get the idea from?

While I was on holiday in Boston in the US I saw something similar. My daughters pushed me to try it out and it was huge fun - so I decided to replicate it in London.

Where do they go?

We run adventure tours called Around London in 80 Minutes, which take in all the tourist attractions including Buckingham Palace, Piccadilly Circus and Hyde Park continuing into the Thames and going past the Houses of Parliament.

Do you think tourists really want their bus to drive into the river?

Absolutely; they're overwhelmed by it.

How many are there?

Three running currently with a view to adding two a month. I've taken on option to buy a total of 32, each one coming into service once a renovation and re-service has been completed.

Do they have names?

Mistress Quickly, Beatrice and Titania.

Have you ever driven one?

Yes, but not on the road as I don't have the appropriate licence. You need a PSV (Passenger Service Vehicle) licence and a boatsman's licence from the Port of London. It's the most regulated method of transport.

Who has travelled on it so far?

Fare-paying tourists of all sorts of nationalities. The personalities that helped to launch it were Stirling Moss and Jenson Button. We asked them because they represent the old and the new - as the Frog does.

What do passers by think?

People continually stop and stare with mouths dropped open. The older folk mouth "duck" because they know how the vehicle was originally used. On one occasion, football fans at Trafalgar Square sang We Love Mr Froggie and then Yellow Submarine at it. If we travel down The Mall, more people look at the Frog than at the Palace.

Is there anything you don't like about it?

No. It's deeply endearing and adds a new dimension to London. It has a major historical role and is given a new lease of life.

What do you normally drive?

A dark blue BMW 323

• Frog tours: 020 7928 3132