Ark, cloud and globe on shortlist for Liverpool's 'fourth grace'

Liverpool, a city seeking a fourth building to supplement the "three graces" that make its riverfront one of the world's finest, shortlisted designs yesterday including a ship's bow in glass, a huge cylindrical "cloud" and a green copper globe etched with a map of the world.

The shortlist of four brings into competition an all-star architectural cast of Will Alsop, Richard Rogers, Norman Foster and Edward Cullinan and ensures that the existing Edwardian graces, which include the Liver Building, will soon be joined by a dramatic new neighbour.

Post-industrial riverbanks in northern England have served Alsop well. His "blinking" Millennium Bridge, which rises between Gateshead and Newcastle across the Tyne, secured architecture's Sterling Prize last month.

For the Mersey, his plans include "the Cloud" – a circular 10-storey edifice decorated with hieroglyphics of Liverpool's 800 years of history – and the Hill, an exhibition space and conference centre.

A garden of light would be created from a row of arches along the promenade with space beneath for a mix of small art dealerships, gift shops and restaurants.

It is a far cry from the showroom selling Mercedes and Porsches that has occupied the six-acre site over the past few decades. "Only a genuinely daring and distinctive design will succeed in revivifying the spirit of Liverpool," Alsop said.

Rogers, chairman of the Government's urban task force, has plans for two towers on the waterfront – one a 20-storey hotel, the other a 30-storey residential building. Beside them would sit a large public space, the "Wintergarden", covered by a translucent roof, which would be lit at night and house a museum and 2,500-seat auditorium.

Foster's offering is the "Liverpool Ark" – which, with a nod to the city's maritime past, peaks in the shape of a ship's bow. The glass-covered Ark would be taller than the Liver Building, reflecting back the colours and details of the three graces and the adjacent red-brick Albert Dock. A viewing platform is planned for the front tip of the building above a covered public space.

Cullinan's globe, covered in aged green copper, would house a 1,000-seat multipurpose performance space. It is designed to provide a new home for a Liverpool theatre company. A new marina for barges and yachts would be created in nearby docks.

Mike Storey, leader of Liverpool City Council, said the designs reflected the city's "once-in-a-lifetime opportunity" and that the winning design had to provide "a statement of intent – that Liverpool is a world-class city with world-class architecture".

The three graces are masterpieces. In his guide to the buildings of England, Nikolaus Pevsner says the three, which include the less flashy Port of Liverpool and Cunard buildings, "represent the great Edwardian imperial optimism and might indeed stand at Durban or Hong Kong just as naturally as at Liverpool".

The 10-storey Liver Building is the finest of the three, capped with the Liver Birds, which have become the city's symbol.

The new building could cost between £150m and £225m and is likely to house a museum celebrating the city's culture.

The four contenders

NORMAN FOSTER

The 'Liverpool Ark' is the least striking plan on the shortlist and very much in line with his increasingly pared-down designs. The tower building is part of an intelligent two-card trick, a monolith to catch the eye from afar, locked into a horizontal slab that juts out over the water like the prow of a passenger liner.

RICHARD ROGERS

He is clearly intent on putting on a fabulous show with this design, one of two show-stopper candidates. Aesthetically, it's poised on a razor's edge. Liverpudlians will be able to chill out in a vast piazza regardless of the weather. Less striking than the Foster scheme from the water but much more attractive from the land side.

EDWARD CULLINAN

These twin towers and stepped blocks are wonderfully decisive. This is a return to South Bank-cum-Barbican modernism, the most obviously attractive grace on the shortlist. Cullinan is going for a total reinvention of the site. Will the original buildings and the surrounding area be lost against these raking waves of modernism?

WILL ALSOP

Currently, the hottest architect in Britain, Alsop is uncompromising. Apart from an attachment to the classical Golden Section system of proportion, he is not interested in formalities of style. His design is a startling collection of parts, including a tower block on columns and a gigantic pouffe of a building. Wild but wonderful.