The first details of Dyson's first electric car have emerged, as the vacuum cleaner-maker looks to take on the likes of Tesla.

Plans for the car, which will be "entirely designed, manufactured and sold" by the company, are on track for a launch in 2021, Sir James Dyson confirmed.

In a letter to staff, the entrepreneur said the car the will contain "fundamentally new technologies and make some inventive leaps".

A number of patents for new cars have been issued, although the drawings "don't reveal what the vehicle will really look like or what it will do", Sir James said, as he called on staff to keep key details secret.

Advances have been made in the aerodynamics, efficiency and vehicle architecture of the car, he added.

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The first patents, which were filed 18 months ago but have been made public for the first time, reveal designs for an off-road vehicle in Dyson's planned line-up, although details of its first car still remain closely guarded.

Patents for the off-road prototype highlight an intention to use "very large wheels" to suit bumpy terrain as well as to improve "range and efficiency".

Dyson has set aside around £2.5 billion to invest in the project, as it leaps into the highly-competitive electric car market alongside the likes of Elon Musk's Tesla.

Telecoms giant BT has ramped up targets for the roll-out of ultra-fast broadband as it kept shareholder dividend payouts unchanged despite falling sales and earnings.

The group reported a two per cent fall in underlying earnings - the group's preferred measure - to £7.4 billion for the year to March 31.

It cautioned that underlying earnings are expected to fall to between £7.2bn and £7.3bn over 2019/20 - the third year of declines in a row - with a drop of around 2% in adjusted revenues.

On a statutory basis, however, pre-tax profits lifted 2% to £2.7bn in the year to March 31 on revenues 1% lower at £23.4bn.

David Roper, one of the founders of Melrose, has announced he is to retire from the industrial buyout firm a year after its £8 billion acquisition of GKN.

The executive vice-chairman said he will step down from the London-listed firm at the end of May 2020.

The 69-year-old set up the business alongside Christopher Miller and Simon Peckham and oversaw a number of major transactions as the company's chief executive between 2003 and 2012.