Tony Blair has used a complicated web of companies for his business activities since leaving Downing Street

Tony Blair has announced he is winding up his secretive money-making empire and using millions of pounds of its assets for charity work.

The former prime minister is said to have built up a £60million fortune since leaving Downing Street nearly a decade ago.

But he is now set to close down the complex network of companies that handles his business activities.

Experts have struggled to untangle exactly how the structure works, with money coming apparently coming in from lucrative global speeches, consultancy and donations to charity work.

Mr Blair said that 'substantial financial reserves' - thought to be up to £8million - would be pumped into not-for-profit activities.

Mr Blair made clear he would still keep a 'small number of personal consultancies for my income'. But 80 per cent of his time will go on unpaid work.

The dramatic move comes after a summer in which the former PM came under heavy criticism from the Iraq Inquiry - the issue which has come to define his time in office.

Since 2007 Mr Blair has created a complicated web of companies to underpin his consultancy, speeches and other work.

In an email to staff today he said that the vehicles - including Tony Blair Associates, Firerush and Windrush - now employed around 200 people and worked in more than 20 countries.

But he wrote: 'It is time to take this to a new level. As I indicated last December at our annual all staff meeting, I want to expand our activities and bring everything under one roof.

'I also want now to concentrate the vast bulk of my time on the Not For Profit work which we do.

'De facto, this has been the case in the past two years but we need to reflect this change in the way we are structured.'

Mr Blair said that meant closing down Tony Blair Associates, and winding up the Firerush and Windrush structures.

Tony Blair has announced he is winding up a complex network of companies that has underpinned his business activities since leaving Downing Street

He added: 'I will retain a small number of personal consultancies for my income, but 80 per cent of my time will be pro bono on the Not For Profit side.'

Mr Blair said: 'The substantial reserves that TBA has accumulated will be gifted to the Not For Profit work.

'We will bring our organisations under one roof and are in the process of obtaining new premises to do so.'