It was a prime opportunity for the Prime Minister to use her political clout to win over the Copeland electorate and impress a new generation of voters.
But during an important pre-by-election visit in which she would usually have a smile virtually tattooed on her face, instead she was seen grimacing at schoolchildren.
The Prime Minister revealed an expression of discontent that may have shocked even her opposing number Jeremy Corbyn to year-six pupils on a visit today.
Theresa May would be expected to have a smile permanently etched on her face during her visit ahead of a by-election in Copeland, but revealed a slightly different expression
The Prime Minister looked less than impressed when a little girl told her how their invention could be used to stop 'turtles getting run over and falling down drains'
She made the unfortunate grimace while talking to pupils at Captain Shaw's CE Primary School in Bootle, Cumbria, as they explained what their award-winning Lego robot could be used for
But in fairness to Mrs May, the grimace was prompted by a rather gruesome image fresh from the imagination of one little girl, concerned about the future of turtles.
As Mrs May talked to pupils at Captain Shaw's CE Primary School in Bootle, Cumbria, they explained their award-winning robot made for the First Lego League contest.
But the Prime Minister looked less than impressed when a little girl told her how their invention could be used to stop 'turtles getting run over and falling down drains' and return them to the sea.
Jamie Reed, the former Labour MP for the Copeland seat, prompted the by-election when he resigned to take up a position at the Sellafield nuclear processing plant.
Ahead of the 2015 General Election, a similar memorable moment of David Cameron was captured as he visited the Sacred Heart Roman Catholic Primary School near Bolton
Mrs May was out supporting Tory candidate, Trudy Harrison, on Wednesday before voters go to the polls on February 23.
Ahead of the 2015 General Election, a similar memorable moment of David Cameron was captured as he spent some time with future voters.
The then Prime Minister, who had been talking of the Tory manifesto on the campaign trail, was talking to young pupils at the Sacred Heart Roman Catholic Primary School in Westhoughton, near Bolton.
But six-year-old Lucy Howarth seemed less than entertained by his presence and was pictured resting her head on the desk next to Mr Cameron.