LONDON (Reuters) - At least 49 billion pounds ($60 billion) of maintenance work at schools, hospitals and prisons in Britain has yet to be carried out, a spending watchdog said on Wednesday, highlighting the real world impact of squeezed public finances.

Finance minister Rachel Reeves is facing growing pressure to cut spending, boxed in by fiscal rules limiting government borrowing and a reluctance to raise taxes any higher than she did in October.

However, the National Audit Office (NAO), which compiled the report, said deferring maintenance could lead to higher costs further down the line.

"Allowing large maintenance backlogs to build up at the buildings used to deliver essential public services is a false economy," Gareth Davies, head of the NAO, said in a statement.

The Labour government said this was the result of "long-term underinvestment" by the previous administration. It was elected last July after 14 years of Conservative Party rule.

A Cabinet Office spokesperson told Reuters the government is taking immediate action to remedy the state of disrepair found across the public estate and is "already investing billions of pounds to deliver critical repairs and rebuild our public services."

The NAO's report on maintaining public service facilities said, however, that the true cost of remediation could be substantially higher, noting that official data on the condition of properties is incomplete and out of date.

Conservative lawmaker and chair of the Public Accounts Committee Geoffrey Clifton-Brown called on the government to "urgently break the cycle of short-term thinking, dither and delay".

The report showed that the Ministry of Defence had the largest maintenance backlog, with an estimated 15.3 billion pounds. Schools and hospitals followed, each with a backlog of 13.8 billion pounds.

($1 = 0.8160 pounds)

(Reporting by Sam Tabahriti; editing by William James and Sarah Young)