Durham Constabulary said the drive to Durham did not breach the rules but the second trip,to the town of Barnard Castle,might have been"a minor breach"of lockdown rules"that would have warranted police intervention".
The force said that had Cummings been stopped by an officer at the time he would likely have been ordered to turn around,but"there is no intention to take retrospective action".
More than 14,000 people in Britain have been fined by police for violating a ban on all but essential travel that was imposed March 23 to help slow the spread of the virus.
Loading
Johnson has resisted calls to fire Cummings,his most senior aide and the architect of the Conservative Party's December election victory,for apparently flouting restrictions that the government imposed on the rest of the country.
Cummings has defended his actions,saying he traveled to ensure that his four-year-old son could be looked after if he and his wife,who both had coronavirus symptoms,became sick. He said he drove to Barnard Castle to test whether his eyesight,which had been affected by illness,was good enough for the long trip back to London.
Cummings'explanation failed to assuage the anger among many Britons who have endured two months of isolation from loved ones during the pandemic and see a double standard at work.