Staff have been ordered to leave the premises and fire crews have been called to the incident. Pictures show at least one fire engine deployed to the scene.

       Sky News’ Ed Conway reported the incident on Twitter ahead of a planned interview with Chancellor Rishi Sunak.

       He tweeted: “Just as we were about to begin our interview with @RishiSunak the Treasury building has been evacuated and a fire engine has pulled up.

       “Not sure what to read into this.”

       HM Treasury is the Government department for the economy and is overseen by the Chancellor.

       The latest official figures published this morning showed UK economic growth slowed down significantly in the last three months.

       The Office for National Statistics (ONS) said the economy grew by 1.3 percent between July and September, down from an expansion of 5.5 percent in the previous three month period.

       The ONS said growth picked up in September to a better-than-expected 0.6 percent but pointed out the overall figure was worse than predicted due to the global supply chain issues.

       Automotive and construction sector was particularly hit by difficulties sourcing materials, the ONS added.

       The latest quarterly results mean the economy is now 2.1 percent below pre-pandemic levels.

       Grant Fitzner, chief economist at the ONS, said: "Growth picked up in September and the UK economy is now only slightly below pre-pandemic levels.

       "This latest increase was led by the health sector, boosted by more visits to GP surgeries in England.

       "Lawyers also had a busy month as house-buyers rushed to complete purchases before the end of the stamp duty holiday.

       "However, these were partially offset by falls in both the manufacture and sale of cars. Notably, business investment remained well down on pre-pandemic levels in the three months to September."

       This is a developing news story, more to follow.