Crossrail has heeded calls from Transport for London (TfL) to refrain from forcing departing staff to sign non-disclosure agreements (NDAs) in light of concerns raised about the organisation's transparency.

NDAs are a type of legal contract that bind former employers to confidentiality restrictions. They attracted controversy in the Harvey Weinstein scandal, when it emerged that a number of his accusers said they had been pressured into signing NDAs that prevented them from speaking out.

During the Crossrail crisis in the summer, when it was announced that the Elizabeth Line would not open in December 2018 as originally planned, London mayor Sadiq Khan raised "serious concerns" about the "transparency and effectiveness of Crossrail's governance" in a letter to the National Audit Office (NAO), which is investigating the delay.

Chair of the London Assembly's transport committee Caroline Pidgeon has also raised concerns over Crossrail's accountability and transparency.

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At the end of last year she asked Khan whether he publicly supported Crossrail adopting a non-NDA policy.

He replied: "Crossrail Ltd is an organisation with its own independent governance. Nonetheless, I support the principle of what you are saying and suggest that Crossrail Ltd should follow TfL's approach on this issue."

He said TfL's position was that no-one leaving the transport body is required to sign an NDA but that they might have to sign settlement agreements, which can include provisions on protecting confidential information.

"TfL's HR team have been in touch with Crossrail's team to ask that clauses in their settlement agreements fit with this principle," he added.

A spokesperson for Crossrail said: “Crossrail Limited has agreed to adopt the principle that no-one leaving the organisation is required to sign a stand-alone non-disclosure agreement which is the same as Transport for London’s position. However, settlement agreements can include provisions protecting confidential information of the organisation provided they are used responsibly and that they do not prevent people from raising legitimate concerns about the organisation. Crossrail Limited will continue to report termination payments as part of the TfL annual report as we did last year.”

Last year TfL was also criticised for signing more than 800 NDAs with departing members of staff between 2016 to 2017.

Pidgeon, who asked about the number of NDAs for TfL's departing staff, said she was "amazed" at the numbers.

“TfL needs to justify this high level of agreements and reassure the travelling public that they are not gagging former staff who should have every right to comment on an organisation they once worked for," she said at the time.

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