The early consequences of Britain voting to leave the European Union has increased the cost of Tottenham Hotspur’s new stadium, according to the club’s director.

In an email to a supporter published online, Donna Cullen said that Brexit had seen the final cost rocket to £800m (US$972.1m, €920.7m) – more than the cost of building the new Wembley Stadium.

When the plans were originally revealed, the 61,000-capacity stadium was expected to cost around £400m (US$486.1m, €460.7m).

Cullen wrote: “Brexit has added a straight 20 per cent on costs for foreign goods due to the exchange rate, overtime working and increased construction costs similarly.

“It is worth remembering that the original cost quoted for the stadium (£400m) was some seven years ago. The new estimated figure (£800m) relates predominantly to the stadium with some elements of substructure for the other builds, particularly the Tottenham Experience.”

She added: “Revised basement works also added to the cost. We are constantly managing costs and will continue to do so throughout the process along with funding plans to ensure the viability of the scheme.”

The Populous-designed stadium – which is being built to host regular National Football League (NFL) games as well as Premier League football – is expected to be completed before the start of the 2018/19 season.