AHMM has reworked its plans to upgrade Denys Lasdun’s IBM building on London’s South Bank for the second time in a year after the brutalist block won a grade II listing from Historic England.

The practice’s original proposals for the office complex, completed in 1983, were floated early last year and envisaged the creation of an extra 20,000sq m of space through the addition of two new storeys.

But the scheme for Wolfe Commercial Properties Southbank – owned by the United Arab Emirates-based Easa Saleh Al Gurg Group – was drawn up before the building was listed, in part for its “architectural concordance” with the neighbouring National Theatre, also designed by Lasdun.

…