BARCELONA architect David Mackay has given his backing to plans for a tall building on the site of the old Woolworth's store in Plymouth city centre.

But the author of the 2003 Vision for Plymouth has called for the city's Design Panel to be recalled to make sure the planned 20-storey tower block is of a good design.

"You can't condemn a building for being too long, or too tall, but it should be good architecture," said Mr Mackay.

He was speaking after the project, by Liverpool Victoria Asset Management, which owns the shuttered Woolworth's building, faced criticism from readers on The Herald's Your Say pages.

The project, which could be completed by the end of summer 2012, would create a completely new city- centre street.

The 20-storey block would sit alongside a second 13-storey tower, together providing apartments for 600 students and crowning a 20,000sq ft exhibition space.

Below that, the ground and mezzanine floors would house up to seven shops, cafes and restaurants, some of them along a new street linking New George Street and Cornwall Street.

Mr Mackay's Vision for Plymouth foresaw the creation of a 'mini-Manhattan' in the city.

The architect said yesterday that a very tall building should be set back from the street to avoid changing its character, and warned against allowing the new lane linking Cornwall Street and New George Street to be too wide.

"The objective was not just tall buildings but to increase the residential population and provide workshop/living accommodation on the ground floor, giving a human scale and presence to the city so lacking within the internal areas of Abercrombie's blocks," said Mr Mackay.

He acknowledged that economic pressures might force the council to accommodate an important private investment in the city centre to generate interest in future investments, but said: "We envisaged three- or four-storey mews-like volumes with a tower facing Cornwall Street alternating with towers on the opposite side."

Mr Mackay said the developers' plan to have first-floor art space was 'fantastic.' All floors above that should be residential, he said: "There could be two towers at either end, or one higher slab in the centre set back from the façade."

Mr Mackay also praised the architecture of the planned Oceanique building at Derry's Cross.

"It could be great," he said. "But the lower volumes fail to match the quality of the tower. There should be more unity, with a cascade of glass."

Mr Mackay also welcomed the multi-use plans for the building, saying: "There is a tendency to have single-use buildings because the financial people back one use or another."

And he said the building should not go much higher than the 20 storeys already planned.

"Twenty-two is really the maximum one can go economically. Higher than that is usually not viable – it's normally done for prestige."