Leaks of information to the Sun: "undermined the budget process," and may have led to a lower tax revenue for the government but yet, no investigation was ever undertaken a court was told yesterday.

Richard Lester, Head of Security for Her Majesty’s Treasury, told an Old Bailey jury that articles in the Sun on the morning of the 2010 budget revealing that fuel and alcohol duty were to rise may have led to people: "rushing out to buy them, leading to a loss of revenue for the government," adding "any diminution of tax coming in leaves the country the poorer." However the official also confirmed that no investigation was ever launched over the alleged leaks.

The evidence came during the trial of Sun Whitehall correspondent Clodagh Hartley who is charged, along with Marta Bukarewicz, with conspiring to commit misconduct in a public office by allegedly purchasing confidential information from a HMRC press officer Jonathan Hall, including details of the 2010 budget.

Cross-examining Mr Lester, defence QC Alexandra Healey noted that, when Alistair Darling was Chancellor, the Treasury confirmed to newspapers that it planned to cut VAT to 15%. "Was this not price sensitive information?" Healey asked. Lester responded that it was "not unusual" for political parties to release proposals that might benefit them, or to see how the public would react to a new measure adding "there is authority there, so it is not a leak."

The Sun journalist's defence team also told the court about events in 2013 when the London Evening Standard was given advance information on the budget and the mistakenly tweeted out a picture of their forthcoming front-page with the details before the Chancellor had risen in the House of Commons. The security head said that he was aware of the incident but drew a distinction between a "leak" which was unauthorised and special advisers giving the media information which was: "agreed by their political masters." Asked to comment further Lester said "Special advisers do all sorts of things we do not know about, identifying if stories came from leaks is something we find very difficult."

Both of the defendants deny the charges, the trial continues.