The 240 pence per Spire share offer is at a 24.4% premium to the stock's last closing price.
Spire said in a joint statement with Ramsay that the parties had reached an agreement on the terms of the deal, and recommended that shareholders vote in its favour.
London-listed Spire, which has major contracts with Britain's state-backed NHS healthcare network, has been hit by a drop in routine patient visits to hospitals during the COVID-19 pandemic, and had already been suffering from fewer referrals to private hospitals before then.
The group, which operates 39 hospitals in the UK, posted an adjusted pre-tax loss of 231 million pounds ($326.80 million) last year, when it treated almost 750,000 patients, after reporting a profit of 9.6 million pounds in 2019. It had said it expects profit to return to pre-pandemic levels this year.
"Ramsay will work closely with the Department of Health & Social Care to ensure all shared objectives are closely aligned and we stand ready to support the NHS in tackling the significant increase in waiting lists and the return of elective procedures in the UK," said Craig McNally, Ramsey's CEO and Managing Director.
Ramsey added that it would engage with Britain's competition regulator over the deal. The UK Competition and Markets Authority may require it to divest certain hospitals and clinics for the deal to go through.
"This is a good bid and should be acceptable to shareholders. But, there will be competition authority issues and getting the deal over the line will not be straight-forward," Graham Doyle, health equity research analyst at brokerage firm Liberum, said in a note.
The deal will deliver high single-digit earnings per share from 2024, Ramsay said, adding that the acquisition will be funded through existing debt facilities.
Mediclinic International, Spire's biggest shareholder with a 29.9% interest, separately said it would vote in favour of the proposal by Ramsay.
($1 = 0.7064 pounds)
(Reporting by Arundhati Dutta and Pushkala Aripaka in Bengaluru; Editing by Jacqueline Wong and Arun Koyyur and Kirsten Donovan)
By Arundhati Dutta