The 178-year-old mutual insurer at the centre of a controversial private equity takeover saga has accused its rival of lobbing in a “hand grenade” to try to disrupt its agreed £530 million sale.

LV=, which was formerly called Liverpool Victoria, has rebuffed the latest approach from larger competitor Royal London, criticising it as a deliberate attempt to derail the sale to Bain Capital with just weeks to go before a member vote.

LV said the proposal from Royal London would see the business split up and result in redundancies and possible closures among its three sites in Bournemouth, Exeter and Hitchin.

LV chief executive Mark Hartigan told the PA news agency he was “disappointed” with the timing of Royal London’s move and urged members to back Bain’s deal.

He said the latest proposal was a “hand grenade to disrupt the process”.

He said: “How extraordinary that halfway through the voting process and we get this intervention.

“Royal London had every opportunity to offer a better deal than Bain and they didn’t.”

He added: “They (Royal London) made very clear that the success of their bid relies on synergies and that means redundancies.”

But for the first time, LV has revealed the financial details of Royal London’s original approach, confirming the group was offering £540 million – higher than Bain’s £530 million.

LV said it was previously unable to release the details due to a non-disclosure agreement, but said the Bain deal remained the only formal offer on the table.

Bosses at LV also said it was “grossly misleading” for Royal London to describe its proposal as a “mutual alternative”, stressing that any such deal would still lead to demutualisation.

LV also claimed Royal London did not want members to vote on its proposal.

Royal London insisted that LV remaining a mutual “is an option” under its approach.

“We do not want to break up LV and would be delighted if the LV board would engage in discussions,” it added.

It marks the latest twist in the takeover tussle, which has taken centre stage as politicians from across the spectrum have united to hit out at the deal, which would see LV’s 1.2 million customer-members hand over ownership of the group.

With less than a month to go until members vote on the deal, concerns are growing over the group’s future in the hands of a private equity firm and the payouts being offered to members, as well as the motives behind the sale.

Under the Bain deal, they would hand over ownership of the group and receive £100 each while with-profits members will be given an additional boost when their policies mature.

Some members have dismissed the payout as being “paltry”.

LV’s board agreed to the Bain capital deal after receiving around a dozen expressions of interest.

Mr Hartigan urged members to “cut through the media storm”.

“Believe me when I say that this is the best and only deal that saves the future of LV,” he said.

He said the 1,400 staff at LV were “extremely worried that the deal we are asking members to vote on is being undermined”.

But there has been speculation over rewards and guaranteed roles offered to Mr Hartigan and management by Bain should the deal go through.

Mr Hartigan admitted he had held discussions with Bain over a management incentive plan, though he dismissed suggestions he is in line to personally gain from the deal as “frankly fanciful and ridiculous”.

Members will be asked to have their say on December 8 or at an online meeting on December 10, with 75% of votes needed to back the takeover and a minimum turnout of 50%.

There are concerns over plans to push through a rule change that will mean it can override the minimum turnout threshold.