The 40-storey office tower is being sold by receivers after one of its joint owners, Germany's IVG Immobilien, filed for insolvency last year.

Co-owner Evans Randall said in April it was ready to invest further, but was unable to agree a new financial structure with IVG.

Agents said the building, whose distinctive curved profile has been a feature of London's skyline for a decade, could fetch in excess of 640 million pounds ($1.09 billion).

Jamie Olley, Head of City Investment at Deloitte Real Estate, called the Gherkin "the most iconic office tower in the City's skyline", adding: "We are confident of maximising returns to the receivers and creditors." 

Designed by architect Norman Foster and located at 30 St Mary Axe in the City of London financial district, the tower houses about 20 firms, including reinsurer Swiss Re.($1 = 0.5897 British Pounds)

(Reporting by Paul Sandle; Editing by Ruth Pitchford)