In the month running up to the Copeland by-election, veterans at Tory HQ were surprised by the almost daily presence of one unusual visitor. Philip May, the PM’s husband, turned up to phone bank for Trudy Harrison nearly every day between 6pm and 8pm. “He was there at least 90% of the days for the last few weeks,” says a source, noting that by contrast Samantha Cameron would attend phone banks once or twice per by-election, usually just as a photo opportunity. A sign of how the Tories threw the kitchen sink at Copeland? Possibly, though there is more to it than that…

Theresa May’s inner circle comprises of just four people: the PM, her chiefs of staff Fiona Hill and Nick Timothy, and her husband. She trusts few outside that group. So, Tory insiders say, Theresa has deployed Philip as her political secret weapon: her personal focus group, amateur pollster and party mole. Those in the room estimate Philip spoke on the phone to more than a thousand Copeland voters and believe the PM used him to gauge opinion, rather than rely on the professional pollsters who let down her predecessor. “He was her personal focus group for voters because she trusts no one else,” says a Tory source. He phone banked assiduously in the Sleaford by-election as well.

There was of course another benefit to having Philip in CCHQ – he could report back on which Cabinet ministers and MPs were pulling their weight. Tories say the proof that Philip is being used as a serious political operative is the fact that his phone banking exploits have not been briefed out to the media, as was the norm with SamCam. An insight into how few people the PM keeps close, and how important those few are…