Keep calm and gag Boris: Expert Brexit negotiating tips for Theresa May

London - UK Prime Minister Theresa May is getting ready for one of the most complex negotiations that she, or anyone, has ever faced.

To help her lead Britain out of the European Union (EU), Bloomberg sought advice from veterans of other high-stakes talks.

They’ve freed hostages, brokered divorces, secured peace deals and poker pots, and their counsel has a common thread running through it: keep quiet.

The prime minister needs to hold her cards close to her chest keep her lieutenants in check and listen more than she talks, they said.

The experts’ suggestions might explain why May has been so tight-lipped since taking office in July. Whether she can hold that line, with European leaders and opposition lawmakers demanding she set out her plans as soon as possible may shape how good a deal she can get for voters.

The hostage scenario

Former Policeman Richard Mullender persuaded the Taliban to free three United Nations workers it had captured in 2004 and has also helped liberate British citizens kidnapped abroad.

He says that when trying to free a hostage, listening is often more important than talking. Only one person should speak to the perpetrator with the rest of the team providing guidance.

That may be easier said than done for May. She has packed her Cabinet with lawmakers such as Brexit Secretary David Davis who, unlike her, built their careers around leaving the EU and are agitating for a clear break, while Foreign Secretary Boris Johnson has already been reprimanded for going off message.

According to Mullender, it’s also important to keep emotions in check and focus on deciphering what makes the other party tick.

"The biggest secrets that people give away will come through the words they speak," he said. "The key tip is really to shut up."

Trade talks

While ministers like Davis and Chancellor Philip Hammond have explained their priorities for the talks, May has given far less away so far.

She should continue to keep as much detail of what she wants to herself, said David Archer, a head-hunter at Circle Square Talent who specializes in recruiting trade negotiators.

"With all negotiations, even if we look at a corporate negotiation, you always have to keep your cards close to your chest," Archer said. "If you show everyone your cards, then you’ve lost the game."