A second serious fault was discovered on the newest bridge over the River Clyde yesterday, raising the prospect of the crossing being closed for up to six months.

The Clyde Arc, nicknamed the Squinty Bridge, has been closed to traffic for almost two weeks since one of its supporting ties broke from its arc and crashed on to the deck.

The 115ft support was said to fall with a bang so loud that some nearby residents thought it was a bomb explosion.

It was originally thought the bridge, which links Finnieston with Govan, would remain closed for a few weeks, but during an inspection by engineers yesterday afternoon a crack was discovered in another of the bridge's 14 steel ties.

Glasgow City Council responded immediately by asking the Clydeport harbour master to close the river to all traffic as a safety precaution.

A council spokesman said it was expected that the Arc would be closed for up to six months. He said: "The bridge was closed last week following the failure of a steel component that connected one of the hangers to the arch.

"The casting that failed has been taken away for inspection and testing and the council, constructors and designers are still awaiting the results of this.

"In the course of an inspection today, a crack was found in another similar connector on a different hanger.

"The council has, as a precautionary measure, requested that all river traffic below the bridge be suspended until further notice."

The spokesman said the crack had appeared "very quickly".

He added that it was not clear if it had been caused as a result of the other tie snapping.

The council said the decision to close the river would have a "minimal" effect on traffic, as that stretch was rarely used for commercial purposes.

Strathclyde Fire and Rescue said last night that it does not anticipate the closure will have any major impact on its Water Rescue Service on the Clyde.

Strathclyde Police's river patrol boats are unlikely to be affected by the closure.

But the closure could cause problems for BBC employees travelling to the new headquarters at Pacific Quay.

Construction of the bridge was considered an essential part of the BBC's move from its headquarters in the west end to the south side of the river.

Following the closure of the bridge, which cost £20m, engineers defended its design.

Gordon Pomphrey, chairman of the Glasgow and West of Scotland region of the Institution of Civil Engineers, said the design, by engineering consultancy Halcrow, was safe.

He said at the time: "While it is a modern design and was built using the most up-to-date methods, it is not so cutting-edge that the security of the bridge should be in doubt."

The bridge has long been contentious. Its construction was held up by legal protests from campaigners who viewed it as the end of shipping on the upper Clyde.

Its 14 semi-rigid steel ties that connect the bridge to its arc were designed to be removed for maintenance.

A team from Edmund Nuttall, the firm that built the bridge and manages it, is carrying out the investigation.