Sir Martin Sorrell has boasted that he is “2-0 up” against WPP seven months after being “electrocuted” by his former company – but insisted he was not out for revenge.

The businessman, who built WPP into the world’s biggest advertising company over 32 years at the helm, was speaking after the announcement of a second big acquisition by S4 Capital, the venture that he set up soon after leaving.

Sir Martin told Sky’s Ian King he was sad about his acrimonious exit from the company after its board launched a probe into an allegation of improper personal conduct.

But he said he did not feel wounded by lurid coverage of the episode, adding that an investigation had found “nothing material” and that he was a “good leaver” from the company.

Sir Martin also offered his thoughts on Brexit.

The businessman, a Remain supporter who backs a second referendum, warned that major investment decisions would not be made amid the current uncertainty.

He felt that Theresa May’s deal was “not the right way”, adding: “I find it a little bit ironic that we’re being told to take this deal because there’s nothing else on offer.

“We should take the very best deal we can possibly negotiate, not the only one that we were able to negotiate.”

But he said the view in the City was that the deal could pass the House of Commons on a second attempt – with “modifications”.

Sir Martin also explained why, at 73, he had no plans to stop working.

“I can’t see myself retiring to the beach or the golf course,” said Sir Martin. “I think golf is for old men. I really want to remain active.”

Sir Martin likened his departure from WPP to being “ejected or electrocuted” and said it “hasn’t been an easy six months” as he builds his new business.

Since his departure, his new venture S4 Capital has bought Dutch digital agency MediaMonks and this week agreed to acquire San Francisco-based programmatic ad firm MightyHive in a $150m (£118m) deal.

He described the venture as a “peanut” which has now “morphed into a coconut” with the latest deal.

Sir Martin said he was now “three quarters or seven eighths” through the process of building up the business, telling Sky News: “The train set is almost complete.”

He said he was “sad about it” when asked about his exit from WPP – in which he remains a major shareholder – and noted that it had just seen “another lurch downward” in its share price.

Sir Martin suggested that his new venture, with revenues of $150m, could hardly be compared with WPP’s $20bn (£15.7bn) – though he admitted that they “do collide” and had done so over both his acquisitions.

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“I guess it’s 2-0 halfway through the first-half of the match,” he said.

“It’s not personal… if ever there was a revenge element to it, the challenge is to build the new age, new era model that will be successful.”