Engineers from Cuadrilla have started work at the Preston New Road site near Little Plumpton, to pour concrete into the two wells drilled there and then remove valves and surface pipework.
It brings an end to ten years of wrangling over the attempts to exploit the gas trapped deep underground in Bowland Shale rock across the county.
Residents had opposed it, saying that hundreds of wells would have to be drilled from Blackpool to Preston, many close to homes and schools, citing problems with pollution and the earth tremors that fracking, the injection millions of gallons of water and chemicals into the rock under pressure to release gas, causes.
Work halted in 2019 after a series of tremors. The Government issued a moratorium on UK fracking in November 2019.
A letter from Cuadrilla this week states: “This work, in industry terminology referred to as ‘plugging and abandoning’ the wells, follows-on from formal notification issued by the Oil and Gas Authority in relation to the plugging and abandoning of both wells. It will take approximately five weeks from rig set-up to complete the work.”
A spokesman for Frack Free Lancashire which is monitoring the work, said: "We are pleased to see that work has finally commenced to plug and abandon the fracking wells at Cuadrilla's Preston New Road site.
"We hope that works will be carried out swiftly and without further distress to local residents, who have already endured this insidious industry for far too long, against local democracy and consent.
"We will never get back the time, energy and emotional investment spent battling against the fracking industry and its dirty PR campaign, but we are looking forward to a future where clean and green energy is prioritised over dirty fossil fuels."
Fleetwood MP Cat Smith said that 32 Tory MPs and four peers had written to the Prime Minister calling for a U-turn on fracking, but this was a mistake amid climate change worries and local opposition.
She said: “It’s a happy day in Lancashire when Cuadrilla plug their unwanted fracking wells. We are not Texas, this was always an inappropriate industrialisation of our beautiful countryside, and the earth tremors it triggered proved it was unsuitable too.
"It’s disappointing to see some Tory politicians still looking backwards at this technology instead of seeking to harness the renewable energy revolution and the benefits it could bring our communities up and down the Fylde Coast.”