- Boris Johnson received a £1,800 stay in an airport lounge on the way to his Spanish holiday.
- Johnson stayed in a luxury villa owned by the Goldsmith family in Marbella.
- Johnson has refused to declare the cost of the holiday itself, saying it was unrelated to his political activity.
Boris Johnson registered an £1,800 stay at a London Heathrow airport lounge, the only cost he has published so far on his holiday to Spain in October.
Johnson's entry in the Register of Members' Financial Interests was updated on Thursday to include the free use of the luxury Windsor Suite at Heathrow Airport on October 7, as he flew to Marbella on holiday.
Johnson has not declared the cost of his stay at a villa in Marbella, which is owned by the Goldsmith family of Tory donors and politicians.
Instead, Johnson registered that stay, without its cost, in the List of Ministers' Interests.
He argued that to do so was appropriate since Zac Goldsmith helped organise the trip. Goldsmith is a former MP who was later given a peerage and a junior ministerial role by Johnson.
Johnson's entry in the list of ministers' interests refers to his "longstanding personal friendship" with the Goldsmiths.
Downing Street has refused to provide any detail on the cost of his stay in Marbella, but reports suggest the villa is commercially available at £25,000 a week.
Officials say it is not necessary to register in the House of Commons's register as the trip was unrelated to Johnson's "membership of the House or with the Member's parliamentary or political activities".
Downing Street has said that Johnson wrote to the Commons Registrar to explain why he does not need to declare the villa stay, but refused to publish that letter.
The lack of disclosure has led to criticism from the opposition Labour Party, which says he should reveal the waived cost of the villa.
Angela Rayner MP, deputy leader of the Labour Party, told Insider: "It is utterly ludicrous that the only donation that Boris Johnson has declared related to his latest freebie luxury holiday is the hospitality he enjoyed in the lounge waiting for his plane."
"The Prime Minister was given a gift by someone that he gave a peerage and a ministerial job to and the Prime Minister needs to tell us the truth about his donations."
The Windsor Suite is frequently used by VIPs and royals. Former Prime Minister Theresa May was given a suite for free 16 times, the news outlet NationalWorld reported.
It is unclear why May's entry said the cost was £4,200, but Johnson declared it as £1,800.
Johnson previously pledged to lie down "in front of the bulldozers" to stop a third runway at Heathrow, which was later approved by the May government. He took a trip to Afghanistan and avoided voting on the issue.