Motorists may have to pay a £3 toll to cross Hammersmith Bridge under a set of plans that could see it fully reopened by autumn 2022.

Hammersmith and Fulham Council has announced that proposals it unveiled in November – where a temporary second deck would be built while repairs take place – have been deemed "feasible" by experts.

It follows a six-week technical study by architects and engineers Foster + Partners and bridge engineers COWI.

The council said this alternative would be £40million cheaper than the £141million repair plan which has been fought over with the government.

And rather than taking until 2027 to complete, it is hoped that this "double deck" solution could allow pedestrians and cyclists to use it again by summer 2022, followed by other vehicles a few months later.

But motorists have been warned they may need to pay a toll of around £3 per journey despite concerns this could encourage drivers to continue using Putney, Wandsworth and Chiswick bridges. The charge would be administered using automatic number plate recognition cameras.

The council would also relinquish ownership of the bridge to a charitable trust, modelled on the City of London Corporation's Bridge House Estates which runs Tower Bridge and four other crossings.

A statement from the council said: "The level of government [financial] support would also dictate the toll or charge, with significant funding potentially reducing the toll."

Last year Transport Secretary Grant Shapps suggested the council pay £65 million of the previously predicted £141 million for repairs, which the council said would be impossible for a local authority to afford.

The news comes nearly two years after cracks were found in the 133-year-old grade II* landmark's pedestals, meaning it had to close to cars and buses immediately to halt the risk of it collapsing.

Those cracks were found to have widened significantly during the heatwave of August 2020, meaning even pedestrians and cyclists were no longer safe to cross. This has caused misery for school children and people who regularly commuted between Barnes and Hammersmith, as once short journeys became one and a half hours by bus or bike.

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Explaining how the double deck plan would work, the council's statement said it would involve "launching a truss structure above the existing road deck with a lower level for pedestrians and cyclists and an upper level for cars and buses."

It continues: "That [technical] study has now confirmed that the existing [bridge] foundations could support the extra load of the temporary truss…

"Elements of the bridge that need repair, including the decking, would be lifted away using the temporary bridge as a works platform and transported by barges to an off-site facility for safe repair and restoration."

Roger Ridsdill Smith, head of structural engineering at Foster + Partners, said: "The feasibility study supports the technical viability of the proposed temporary crossing, showing it that it has the potential to be significantly cheaper than a scheme that repairs the bridge in situ. It also offers the possibility of the bridge reopening earlier than previously envisaged."

Council leader Stephen Cowan said: "We are proposing a twin-track solution which reunites maintenance funding with transport use and puts the bridge into a charitable trust, similar to the Bridge House Trust that cares for five of London's most historic bridges."

The Hammersmith Bridge Task Force, chaired by Baroness Vere, will meet next week to discuss the technical study results. An outline financial plan has also been submitted to the Transport Secretary.

It is hoped that planning permission and procurement of contractors could be completed by the end of 2020.