THE £600 million Mersey Gateway has reached an important milestone with work starting on the construction of a temporary trestle bridge at Wigg Island in Runcorn.

The structure will stretch across the River Mersey providing construction teams access to the estuary so that they can start building the new bridge.

It will be 1,000 metres long and nine metres wide when complete.

Halton Council leader, Clr Rob Polhill said: "It is great to see the first real signs of construction activity taking place.

"The Mersey Gateway is becoming a reality. However it's important to remember that it's not just a physical structure. The bridge will transform our local area, connecting communities and bringing regeneration and investment opportunities throughout Halton and the Liverpool city region."

Merseylink awarded north west firm SPI Appleton a multi-million pound contract to construct the trestle bridge.

Approximately 140 steel piles will be driven 16 metres into the ground to support the temporary structure. Each pile measures 20 metres long and weighs three tons.

Hundreds of concrete slabs are being produced for the bridge roadway.

Engineers will start work on the trestle bridge on the northern side of the river at Spike Island later this month. The two structures will meet in the middle of the river in early 2015.

Hugh O'Connor, general manager for the Merseylink Consortium, said: "This is a significant event for Merseylink and highlights the progress we are making in our challenging three-and-a-half-year construction programme."

Two large cranes were recently transported on a barge up the Manchester Ship Canal from Liverpool Docks to a construction compound at Wigg Island.

In the coming months, final demolition work will be carried out around Ditton, Astmoor, Catalyst Trade Park, Victoria Road and Hutchinson Street.

The road network at Bridgewater interchange in Runcorn will be upgraded.

Three pylon cofferdams will be constructed in the River Mersey from floating barges.