Four British banks have a $5 billion combined exposure to Dubai World, making them the biggest foreign creditor group at the Dubai state-owned conglomerate, the Financial Times said on Thursday.

The report, citing bankers and advisers, said Royal Bank of Scotland was the most exposed with between $1 billion and $2 billion. HSBC, Standard Chartered and Lloyds Banking Group had exposure of about $1 billion each, according to the report.

The estimates were broadly accurate, several bank industry sources told Reuters.

All of the banks declined to comment.

Emirates NBD was the biggest creditor with outstanding loans of $3 billion, the FT said. The bank declined to comment.

The report confirms that British banks have far greater exposure to potential problem debts in Dubai than their global rivals, as shown by several sets of loan data.

UK banks have loans totaling $50 billion into the United Arab Emirates, out of total loans of $123 billion by international banks, according to statistics from the Bank of International Settlements (BIS).

But there remains a lack of clarity on where exposures to Dubai World lie and how wide the issue will spread.

The FT said much of the UK banks' lending is to the still functioning parts of Dubai World, including ports operator DP World and the Jebel Ali Free Zone.

Dubai World unveiled a $26 billion debt restructuring plan on Monday, after worries about debt problems have shaken investor and creditor confidence in the past week.

As a result of the restructuring plan RBS's exposure would be about $700 million and Standard Chartered's exposure would be about $350 million, the FT said.

The four UK banks are among six creditors who are leading a committee of Dubai World's creditors, which will meet the company next week, according to an Abu Dhabi bank executive.