The shopping centre giant that operates landmark sites such as The Trafford Centre, Lakeside in Essex and the Metrocentre in Gateshead is to be acquired by Hammerson, the company behind the Bullring in Birmingham, Victoria Quarter in Leeds and Cabot Circus in Bristol, in a move which will create a £21bn pan-European portfolio.

The boards of Hammerson and intu Properties have reached agreement on the terms of a recommended all-share offer by Hammerson to acquire the entire issued and to be issued share capital of intu. The transaction values Intu at £3.4bn

The enlarged group will be led by David Atkins, chief executive, and Timon Drakesmith, chief financial officer, will be called Hammerson plc, and will look to harness the talent in both companies.

David Tyler, the chairman of Hammerson, will be the chairman of the enlarged group. John Whittaker, deputy chairman of intu, will become deputy chairman of the enlarged group. John Strachan, chairman of intu, will join the board of the enlarged group as senior independent director. The enlarged group overall will have six directors nominated by Hammerson and four directors nominated by intu.

David Tyler, chairman of Hammerson, said: "This transaction will deliver real value for shareholders. The financial strength of the Enlarged Group and its strong leadership team will make it well-placed to take advantage of higher growth opportunities on a pan-European scale."

David Atkins, chief executive of Hammerson, added: "The acquisition creates a leading pan-European platform of desirable retail and leisure destinations which are better positioned to serve the needs of our retailers, excite our customers and support our partners and communities.

"I hold intu's high-quality centres in high regard and I look forward to working with a strengthened team to enhance the performance of our entire portfolio."

John Strachan, chairman of intu and proposed senior independent director of the enlarged group, said: "Intu offers high-quality retail and leisure destinations in the UK and Spain, which when merged with Hammerson's own top-quality assets in the UK, in France and in Ireland, present a highly attractive proposition for retailers and shoppers in Europe's leading cities.

"I am proud of the financial and operational success that Intu's management team has delivered and pleased to see that the intu brand will continue."

intu's UK shopping centres are: intu Lakeside, Essex; intu Merry Hill, West Midlands; intu Metrocentre, Gateshead; intu Milton Keynes;  intu Potteries; intu Trafford Centre, Manchester; intu Uxbridge; intu Victoria Centre, Nottingham; intu Watford; Manchester Arndale; St David's, Cardiff; and The Mall, Cribbs Causeway.

Hammerson is a FTSE 100 owner, manager and developer of retail destinations in Europe. Its portfolio has a value of about £10bn and includes 23 prime shopping centres, 18 convenient retail parks and investments in 19 premium outlet villages, through its partnership with Value Retail and the VIA Outlets joint venture. Key investments include Bullring, Birmingham, Bicester Village, Oxfordshire, Dundrum Town Centre, Dublin and Les Terrasses du Port, Marseille.