Operators of the i360 must start paying back the loan it owes the council or face “decisive action”, Labour councillors have warned.

The Labour group on Brighton and Hove City Council have said that the council should reserve the right to take control of the seafront attraction if it remains in default to its debt obligations.

The i360 now owes the council almost £48 million, including interest, and has been told to make payments totalling at least £1 million this year in a special meeting of the council’s policy and resources committee.

The viewing tower has repaid £5.8 million so far but, under its original repayment schedule, had been due to stump up almost £18 million by now.

A spokesman for the Labour group said that, if it takes control of the council in May, it would give the i360’s operators six months to start making loan repayments and would take “decisive, interventive action” if it failed to do so.

Such measures could include finding new operators to improve the performance of the business.

He said: “Labour’s position has always been that the i360 should never have been financed with public money - it was Green and Conservative councillors who lumbered the council with £44 million in debt and this reckless use of public funds in pursuit of a vanity project was an unforgivable lack of judgement.”

Councillors agreed in the meeting earlier this week to require the landmark to pay the council a minimum of £1 million over the next financial year in order not to add to its financial burden.

Council leader Phelim Mac Cafferty described the i360’s repayment situation as “urgent” and said the repayment of as much of the loan as quickly as possible is a “number one priority”.

He said: “We need to feel confident the attraction is safe in their hands, that they have a robust plan and that the city will see results as fast as possible.

“We have called for a specific plan for both the upcoming summer season as well as a longer-term plan which will be forged from testing its efficacy in the coming months.”