Ecclesiastical will offer all brokers a cast-iron guarantee that it will not poach their clients, in a bid to build market share in industrial insurance.
The new terms-of-business agreement, to be launched within the next six weeks, will apply to all brokers, not just Ecclesiastical's agencies or partners, and will stay in place for two years after termination of the contract by broker or insurer.
Intermediary operations manager Joe Gray said the agreement took about a year to develop.
He believed it was the first agreement of its kind to be offered by an insurer, but said it may be picked up by other companies.
“I hope it makes insurers uncomfortable and they see a move of business away from them to us,” he said.
Ecclesiastical had gross written premiums of £250m last year.
Its biggest intermediary business covers commercial operations, independent schools, care homes, charities and professional practices.
Gray said Ecclesiastical's push into the industrial market, launched last October, had been slower than it had expected, mainly because it had found it difficult to attract the quality underwriters required.
The company said last year that it would appoint a further six underwriters, to make a ten-strong team.
However, it has appointed only seven of the ten, despite conducting more than 50 interviews and receiving hundreds of CVs.
“We've set our standards extremely high and we've refused to compromise, because we can't afford to lose our shirt,” Gray said.
He said it was hoped the new agreement would give the company the push into the sector it needed.
“It's part and parcel of our decision to push into industry with partnership brokers,” he said.
“Every man and his dog puts partnership on the table, but it never seems to be a two-way thing.”
Both the British Insurance Broker's Association (Biba) and the Institute of Insurance Brokers (IIB) have welcomed the agreement.
Biba spokeswoman Jennifer Weller said it was hoped other insurers would follow Ecclesiastical's lead. “It's something we've wanted to achieve for some time and our brokers would like to see it adopted further,” she said.
IIB director general Andrew Paddick said: “I just wish the rest of the market would follow suit, and I'd be very suspicious of any company that doesn't.”