Herbert Smith and SJ Berwin have won lead roles as Norway's Norges Bank Investment Management agrees to buy a 25% stake in the Queen's Regent Street property portfolio for almost half a billion pounds.

The deal is expected to see Norges, which manages the Norwegian Government Pension Fund Global, pay £448m to buy the 150-year lease on the property portfolio from The Crown Estate. It marks the fund's first investment in real estate since the Norwegian Government gave permission to invest in the class on 1 March.

Herbert Smith is advising Norges with a team led by City real estate partner Jeremy Walden.

Meanwhile, SJ Berwin is acting for longstanding client The Crown Estate on its sale of the stake. Real estate head Bryan Pickup (pictured) and City real estate partner Helen Willett are leading the team, with tax partner Giles Bavister also playing a significant role.

The deal will see the Norwegian fund receive 25% of the net income from the properties, while The Crown Estate retains 75%. The portfolio consists of 113 buildings, with retailers on Regent Street including Apple, Burberry, Banana Republic and Hamleys.

Norges' investment comes on the back of The Crown Estate's Regent Street regeneration programme.

Norges Bank Investment Management got the greenlight in March this year to invest as much as 5% of its assets in real estate in exchange for decreasing its fixed-income investments. The Regent Street deal is expected to complete by the end of March 2011.