[5][6] Johnson had an interest in politics from an early age, growing up in the 1980s he was aware of the societal changes in the UK (particularly in the industrial areas of North East England).

[5][6] Johnson was selected to be the Labour candidate by a vote of local party members in November 2020, beating the Cambridge city councillor Katie Thornburrow.

[19] In his first week in office, Johnson cancelled plans for the Cambridgeshire Autonomous Metro project that James Palmer, his Conservative predecessor, had supported.

[20] After suspending work on the proposed autonomous metro, Johnson commissioned a new transport plan focused on areas that have suffered from deprivation and equality, and on reducing carbon emissions.

[22] During his first year in office, he officially launched the re-opened Soham station making sure that his predecessor James Palmer, who had been responsible for much of the project, was in attendance at the opening ceremony.

[26] The campaign was successful resulting in Mark Harper, then Secretary of State for Transport, annoucing that the Government was expecting the Train Operators to withdraw the proposals.

[28][29] In December 2023, Olympic gold medallist Chris Boardman, England’s active travel commissioner at the time, visited Cambridge to see the work going on in the county to get more people out of their cars.

[31] Johnson said that the Combined Authority had "pivoted" to ensure active travel within the county is a "high priority" and viewed through the lens of public health.

[32] After the election of a Labour Government in July 2024, the inaugural meeting of metro mayors and Prime Minister at 10 Downing Street saw Johnson wearing a cycling pin in memory of his friend.

The new buses are funded by the Cambridgeshire and Peterborough Combined Authority, Department for Transport, Greater Cambridge Partnership (GCP) and Stagecoach East.

Examples include: improvements to the A141 at St Ives,[52] a new bridge at Kings Dyke to remove delays at a level crossing[53] and in Peterborough at the A1260 Nene Parkway Junction 3.

[55] In June 2021, Johnson made sure that all combined authority staff were paid a living wage and started discussions with trade unions.

[57][58] In September 2023, the Combined Authority agreed to invest £2m in a Carbon Net Zero centre at the College of West Anglia in Wisbech which is about half the monies required.

[62] In November 2024, together with the Mayor of Greater Manchester Andy Burnham Johnson, opened The Glasshouse, a new centre in Hills Road, Cambridge for science and tech firms to share ideas and expertise.

[67] In September 2024 Johnson was one of nine UK metro mayors who together with Jamie Oliver pledged to stop junk-food advertising and prioritise children’s health.

[68] In June, Johnson announced a plan to submit a bid for the combined authority to become the UK City of Culture focused on Peterborough, Cambridge and Ely.

[70][71] In August 2021, he won the support of the combined authority to provide £1.1m to a development project in the town of March in order to prevent it losing a government grant of several more millions of pounds.

[72] On 14 November 2023 he was found to have breached the authority’s code of conduct in relation to “civility” and “disrepute” for which he was asked to make a written apology.

[5] From November 2022 he took four months leave of absence from his mayoral duties while he underwent heart surgery and recuperation under surgeons at Papworth Hospital.