Mitsui Fudosan has retained Stanhope as development manager as part of restructureThe 12-storey extension will contain around 100,000sq m of floorspaceTunnels for Crossrail 2 will be paid for by Mitsui Fudosan as part of the deal1/11show captionJapanese developer Mitsui Fudosan has taken control of the delayed 1.1bn extension to the British Library and promised the project will start construction next year.The Tokyo-based real estate firm has taken full ownership of SMBL, the schemes development partner which had previously been a JV between itself and Stanhope, and retained Stanhope as development manager.It comes more than a year and a half after Camden council approved the RSHP and Arup-designed project in January 2023.One of the biggest construction jobs in the capital, it will add a 100,000sq m groundscraper containing office and library space to the side of the grade I-listed 1970s landmark.Less than 10% of the new 12-storey building will contain library space, with the rest reserved for offices targeted primarily towards life sciences occupiers and a new headquarters for the Alan Turing Institute.Mitsui Fudosan said the scheme, which was signed off by Sadiq Khan last July after a protracted stage two approval process, will start construction in 2026 and complete in 2032.The British Library was built in the 1970sNo contractor has been appointed yet, although a timeline included in a construction management plan as part of the original planning application sets out plans to make an appointment within nine months of final planning approval.It is understood that 5,000sq m of underground passageways on the site intended as safeguarding for the future Crossrail 2 project will be funded by Mitsui Fudosan. The tunnels and shaft, which descend seven storeys beneath the site, were part of a deal agreed between the developer, Stanhope and Transport for London to secure the site.Mitsui Fudosan chief executive Takeshi Iwama said the deal to take control of the scheme represented a major milestone in the evolution of an exceptional opportunity.Our development commitment represents what we believe to be one of the largest single real estate investments into London by a Japanese company to date, he said.We have already acquired significant expertise in the life sciences sector across Japan and the US over almost a decade and will be bringing this to the British Library extension development, our first in this sector in Europe.Tunnels for Crossrail 2 will be paid for by Mitsui Fudosan as part of the dealStanhope chief executive David Camp said the scheme had been one of the most complex projects in pre-development, with many twists and turns over seven years since SMBLs selection by the British Library.Getting here has required patience, skills and teamwork between our team at Stanhope, Mitsui Fudosan, the British Library and neighbours such as The Francis Crick Institute as well as the local community and TfL. Our thanks to them all for their cooperation. We now move on to full delivery mode and so our partnership with British Library will continue and we look forward to starting on site next year.The scheme also includes the controversial demolition of several buildings to the north of the main library, including the 2007 British Library Centre for Conservation, designed by Long & Kentish.Others working on the project include QS Alinea, engineer Arup and landscape architect DSDHA.