Police now say the closures of both bridges across the Forth and the M90 motorway will be put back from 4pm until 6pm.  

The force announced at 3.20pm that road and rail traffic across the Forth would be suspended for two hours after "exposed wire" and what's thought to be explosive materials were found next to the road bridge. 

A controlled explosion will be carried out. 

A statement from Police Scotland said: "This is following the discovery of materials believed to be used in the demolition process at the site of the new Forth road rridge (Queensferry Crossing). 

"Although there is no immediate danger to the public, a decision has been made to dispose of these materials with the assistance of the Explosive Ordinance Disposal Unit (EOD) and to close the road as a precaution during this time.

"The Forth Bridge will also close temporarily while the controlled explosion takes place.  We are working with British Transport Police and Network Rail to facilitate this. 

Chief Inspector Irene Ralston of Police Scotland said:  “Exposed wires were discovered today at the Queensferry Crossing, and while this is poses no immediate risk to the public, as a precaution we are compelled to close the Forth Road Bridge and the M90.

Police Scotland will continue to update the public on Police Scotland Facebook and Twitter with developments, including information on any further road closures.