Watford's lighthouse unveiled

A lighthouse in Watford has been named as one of the best new houses in the world.

It is one of Britain's first zerocarbon homes and is seen as a prototype for other environmentally friendly new-build housing.

It is also among properties in and around London on a 25-strong longlist of developments worldwide in the running to be named house of the year.

Judges will meet tonight at the Royal Institute of British Architects in Portland Place to select the winner.

Sara Mercer, assistant editor of WorldArchitectureNews.com, which organises the awards, said: "With hundreds of entries from around the world, it is a real achievement to get on to the longlist.

"The fact there are so many projects representing London and the South-East is a great reflection of the quality of architecture here."

The five judges, led by Richard Coleman, who has worked on several landmark developments including the Gherkin, are looking for originality, innovation and sustainability as well as how the project overcame a difficult context.

The British houses are up against homes in Austria, Spain, Croatia, Japan, Australia and America.

The most unusual design is from Mexico, where cave-like rooms filled with vegetation have been created inside what looks like a giant shell. Other contenders include a pyramid-shaped house in Japan made from acrylic and a home near Melbourne resembling an exploding letter K.