Lambeth Council chiefs have said they are seeking "urgent meetings" with Croydon Council over the future of the Upper Norwood library, after Croydon announced it had pulled out of the deal.
The library, which had been jointly run by the two local authorities, now faces an uncertain future.
In a broadside at his opposite number this morning, Croydon chief executive Jon Rouse blamed Lambeth’s "fundamental breach" of the agreement’s terms in a letter to Lambeth chief executive Derrick Anderson.
But in response, councillor Florence Nosegbe, Lambeth cabinet member for culture and sport said this afternoon: "We want to continue to work in partnership with Croydon to deliver local services for local people. We have made our financial contribution for this year and expect to see the service continue.
"It goes without saying that we are extremely disappointed that Croydon have attempted to dissolve this partnership which has come without prior warning or consultation with us as partners, or with local residents and staff. Their public statement today can only serve to threaten the future of the library.
"Lambeth remains committed to the Upper Norwood Joint Library and keeping our side of the arrangement. We are today formally asking Croydon to reconsider their decision, and are seeking urgent meetings to clarify their position."
In his letter to Mr Anderson, Mr Rouse cited Lambeth’s refusal to attend the recent annual general meeting, in protest of no Croydon local ward councillors placed on the committee.
Mr Rouse also accused Lambeth of "failing to cooperate" at the 2010 AGM, resulting in "no effective oversight" of the library’s management for two years. Croydon Council said it would ensure the library remained open while the two councils decided what happens next.
But with the library situated in Lambeth territory, it has placed the onus on Lambeth council to decide if it wants to take on the full running of the library.
Staff employed at the library will continue to be paid, Croydon council confirmed. It has set a deadline of seven days for Lambeth council to respond.
Councillor Sara Bashford, cabinet member for customer services, culture and sport at Croydon Council, said: "We have a responsibility to our residents to spend their money prudently and within the letter of the law, and with Lambeth boycotting its management role this is impossible."