The identities of hundreds of NHS doctors and officials receiving payments from drugs firms are likely to be kept secret despite the publication of a new “transparency register” this week, the Telegraph can disclose.

Up to half of medics and other health service staff working for pharmaceutical companies alongside their day jobs have refused permission for their names to be included in a new online database.

The publication of the register follows recent controversy over the practice of NHS staff being paid by drugs companies, with the industry claiming the data would allow the public to see which officials were receiving funds from the firms.

From Thursday, under rules agreed by pharmaceutical companies across Europe, each firm was meant to publish a breakdown of the payments they make to individual “healthcare professionals” (HCPs) in the UK – largely doctors and NHS officials.

But a private industry analysis conducted by Ernst & Young (EY) in April and seen by the Telegraph shows that as few as 52 per cent of doctors and officials working with drugs firms had agreed to be included in the database. Industry sources conceded that the final proportion was likely to be even lower, with the numbers withholding consent running into the hundreds.