Shadow chancellor John McDonnell has called on the UK Government to explain why it is giving Saudi Aramco $2billion in credit guarantees.
The treasury announced earlier this month that it would be providing the energy giant with the loan guarantee.
At the time it was reported that it was so the Middle East firm, which is considering the London Stock Exchange (LSE) as one possible venue for an initial public offering (IPO), could buy goods and services from Britain more easily.
A UK Government spokesman denied it was an attempt to lure the company to the LSE for the floatation.
Mr McDonnell, a Labour MP, tweeted yesterday: “The Chancellor & PM must clarify on what basis a taxpayer $2bn loan guarantee to Saudi Aramco is in public interest.”