Concerns about the size of the new dock at BAE's proposed frigate factory in Scotstoun underline how far things have changed on the Clyde since the heady days of the first half the 20th century.

Such concerns also remind us that future options to build new classes of both civilian and military ships will be limited without a great deal of extra investment.

Clyde shipyards used to make the largest ships in the world. The battlecruiser Repulse, at 32,700 tons the biggest ship built by the UK during the First World War, was assembled at Clydebank. So was World War II giant Battleship Vanguard, which at 50,000 tons was the largest warship ever built for the Royal Navy.

Of course, these warships were small compared with the famous transoceanic liners built in the west of Scotland. The original Queen Elizabeth, built for Cunard in the 1930s, displaced more than 83,000 tons and had a width of 36 metres.

Today commercial vessels are getting bigger, as globalization and the lure of the leisure pound has shipbuilders pushing the boundaries. Maybe it is unrealistic that Scotland will ever be a major player in world ship-building again. Without a dock that can handle the largest ships, it is even less likely to happen.

Dr Phillips O'Brien is Director of the Scottish Centre for War Studies at Glasgow University.