A clutch of Croydon's libraries could be shut down as pressure grows on the council's budget.

"DIY libraries", run by community groups, are being considered as a way to keep threatened parts of the service running.

But campaigners warned the strategy could lead to struggling "second-rate libraries".

Councillor Timothy Godfrey, cabinet member for culture, leisure and sport, said Croydon Council would "do everything to avoid" closures but that central Government funding cuts could force the authority's hand.

Up to nine of Croydon's 13 libraries are likely to be at risk, with those that are lesser-used - such as Bradmore Green, in Coulsdon, and Shirley - mostly likely to close.

The council is obliged by law to provide a "comprehensive and efficient library service", meaning it could face legal action if it cut deeper.

Coun Godfrey said: "How do you determine what comprehensive and efficient is? It has to be quite a good service and quite a wide-ranging one.  

"What a core service legally would probably be is Central library, Thornton Heath, Ashburton and Selsdon, so you've got a geographic spread, and the home book service.

"That's probably the defendable legal minimum that you could provide."

He added: "Councils like Lambeth are looking at more community partnerships, more DIY libraries and things like that, so that you can keep every library open that's possible. That's the route we're heading to.

"If you look at it completely dispassionately, there are some weaker libraries which are the very small ones with very few people going in.

"They are to my mind ideal for partnerships but equally they are probably the most difficult to achieve."

Upper Norwood library, which is funded jointly by Croydon and Lambeth councils, is now run by a community-run charitable trust founded to protect it from cuts.

But the library face an uncertain future ahead of likely funding reductions and Robert Gibson, a campaigner who has played a central role in the trust, predicted the model may not work elsewhere in Croydon.

He said: "It is difficult even in Crystal Palace but if anywhere can make it happen it is a very activist-minded and community-minded place that like that.Your Local Guardian:

At risk: Shirley library is one of the "weaker" libraries threatening with closure

"The problem is areas where they don't have that. You can often get a wave of initial volunteers but trying to sustain that model is very difficult.

"Where you have five really good libraries and some second-rate volunteer libraries, those libraries tend to struggle."

Croydon Labour's manifesto ahead of last year's local elections pledged not to close any of the borough's libraries. The group also joined campaigns against plans to close six libraries in 2011, when the council was Conservative-run.

The authority ultimately dropped the proposals four years ago, and Coun Tim Pollard, now leader of the Conservative opposition group, predicted history could repeat itself.

He said: "You can make a perfectly logical case for [library closures] but people don't want that. They want the council to make other choices.

"We backed away from it and I would imagine that the same would happen again. People aren't any less passionate about their libraries than they were three or four years ago."