Developers behind the 1 Silk Street scheme have been told to confirm whether the protected birds are breeding on the site before construction can begin. Peregrine falcons carry the highest level of legal protection in the UK, making it a criminal offence to disturb them during nesting season.

The issue poses an early challenge for Labour, which has pledged to cut back environmental red tape it says is slowing down national construction efforts. Wildlife rules have increasingly frustrated major projects, with HS2 spending £100m on bat‑protection measures and other schemes facing similar hurdles.

While falcons rarely stop developments entirely, they often trigger costly delays. Battersea Power Station’s £9bn redevelopment included a £100,000 “nesting tower” to lure the birds away from its chimneys. Peregrines have also disrupted works at Britannia Bridge in Wales and a transmission tower in Lincolnshire.

Any activity that risks disturbing the birds requires a special licence from bodies such as Natural England.

The Barbican project, formerly home to law firm Linklaters, includes plans for two 20‑storey towers.