Tata Motors has officially announced that it has entered into a "definitive agreement" to buy Ford's Jaguar and Land Rover brands for £1.15 billion.

Tata has comitted to following an existing five-year plan to invest in and develop the car manufacturing businesses.

The transfer of ownership to Tata Motors is expected to close by the end of the next quarter, subject to applicable regulatory approvals. Ford will then contribute up to approximately $600m (£300m) to the Jaguar Land Rover pension plans.

Negotiations for the deal had been strung out, not because of haggling over the price, but because of the need to negotiate supply contracts under which Ford would continue to provide engines for both marques.

Ratan Tata, chairman of Tata Sons and Tata Motors, said: "We are very pleased at the prospect of Jaguar and Land Rover being a significant part of our automotive business.

"We have enormous respect for the two brands and will endeavour to preserve and build on their heritage and competitiveness, keeping their identities intact. We aim to support their growth, while holding true to our principles of allowing the management and employees to bring their experience and expertise to bear on the growth of the business."

Tony Woodley, joint general secretary of Unite the union, said that Tata was the best option for Jaguar Land Rover.

He said: "We would have much preferred Ford to keep the companies in the family, so to speak, especially with Land Rover being so profitable.

"But with the commitments Tata have given to the future of Jaguar Land Rover and the long term supply agreements for components, especially engines from Bridgend and Dagenham, we're obviously pleased they are in the game."

Roger Maddison, Unite's national officer for the automotive industry, has been quoted as saying the deal has officially gone through.

Maddison said: "Today's deal is really good news for the UK automotive industry and the thousands of people who work for Land Rover Jaguar and its' supply chain.

"Unite has secured written guarantees for all five UK plants on staffing levels, employee terms and conditions, including pensions, and sourcing agreements. The sale ensures our members futures and we look forward to working with Tata."

Indian carmarkers, Mahindra & Mahindra and Bajaj Auto have also given a thumbs-up to the deal. Commenting on the development, Mahindra Group MD and vice-chairman Anand Mahindra, whose company was also in the race for acquiring the Ford Motors' brands, said: "The acquisition of the Jaguar and Land Rover brands will make the world sit up and take notice of India's growing prominence in the global automotive arena. I wish Tatas every success for the future."

However, Tata and Ford are yet to officially announce that the sale has gone through.