The Essex county councillor responsible for finance for the county has refused to explain publicly why the council has built up reserves of more than £103 million for waste.

Since 2007/8 Essex County Council has increased the amount of reserves it has held for waste provision by more than £90 million – from around £11 million.

But when Cllr Gagan Mohindra was asked at a policy scrutiny meeting by Cllr James Abbott over its huge restricted waste reserves, he said it must remain in private.

Cllr Abbott said: “In the restricted reserves the waste reserves has now topped more than £100 million. And we know in the budget that the forecast is to be sharply upwards in the coming years.

“Can you explain rather just around vague terms what specific drivers are behind that? That total is now around half of the total restricted reserves.”

The council has previously said it needs reserves of almost £100 million to meet obligations of the 25-year life of the PFI contract, signed in 2012, that envisaged a waste plant built and operated by UBB capable of annually treating up to 420,000 tonnes of residual waste, trade waste, bulky waste, street sweepings and waste from household waste recycling centres, along with a smaller proportion of local trade waste from Essex and Southend councils.

However it has refused to elaborate what any “contingency arrangements” could be.

Cllr Mohindra said: “This is an ongoing legal issue and I am uncomfortable discussing this further in a public forum.