He was joined by Conservative by-election candidate Jill Mortimer and defending Tees Valley mayoral candidate Ben Houchen as they toured medical diagnostics firm Hart Biologicals, on the Queen’s Meadow Business Park, before he surprised people in Mildenhall Close, on the Fens Estate, with a short walkabout. Here is his day in pictures. Mail pictures by Frank Reid.
5. Laughing matter
Will Mr Johnson still be smiling come by-election day on May 6? Photo: Frank Reid
7. That's Rich
Kevin Richardson, right, with Boris Johnson in Mildenhall Close, Hartlepool. Photo: Frank Reid
8. Hat'll do nicely
The PM meets Mildenhall Close resident John Quinn during a surprise walkabout on his way out of town. Photo: Other 3rd Party
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