A number of fire stations in Berkshire could be forced to shut because the service cannot recruit enough part-time firefighters.
Retained firefighters run 11 stations - more than half in the county - but a review of operations is under way.
A fire service spokeswoman said unless more staff could be found up to four of them could be closed.
Sonning has already shut and Cookham, Pangbourne and Wargrave stations are most at risk.
'Massive underspend'
Retained firefighters are part-time firefighters who have jobs elsewhere and respond to emergency calls when needed.
They need to live within a mile or three minutes of the station where they work.
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With more and more employers unable to release their staff... you can see how this would impact on the availability of retained firefighters”
End Quote Royal Berkshire fire service spokeswoman
Royal Berkshire Fire and Rescue Service (RBFRS) said it had an underspend of £548,000 in its budget, "a significant portion of which was funding identified to pay for retained firefighters".
Richard Coates, an independent fire consultant, said: "Berkshire doesn't have to save money, it's had a massive underspend for the last two years so it's got the money to pay for retained firefighters.
"If you go and close retained fire stations, and we think it may be as many as three or four closing, which is 20% of all the fire stations in Berkshire, this is going to increase your attendance times to any fire incidents."
Sonning station closed two years ago and Cookham has been temporarily shut but is not expected to reopen, Mr Coates said.
The service has no shortage of full-time firefighters but needs to recruit at least another 32 part-time staff.
The spokeswoman said: "Retained firefighters provide varying levels of cover, so in actual fact we need to recruit more than 32 people to ensure that the number of retained firefighters on our stations is sufficient to support fire cover.
"With more and more employers unable to release their staff, or self-employed people unable to turn down business for firefighting duties, especially during the day, you can see how this would impact on the availability of retained firefighters."
The review group includes retained and full-time firefighters, specialist managers and the Fire Brigades Union and a report is due to be published in the autumn.
In light of this would it be time to extend the 3 minute to station requirement for retained fire fighters? I for one would apply but fall just short of the 3 min limit.