He had said he would step down if police had issued him with a fine.
UK opposition leader Sir Keir Starmer has been cleared of breaking COVID lockdown rules.
Durham Police had opened an investigation after "significant new evidence" came to light about a gathering in which he was filmed holding a bottle of beer.
His critics said the incident on 30 April 2021 -- at the office of City of Durham MP Mary Foy -- was a breach of lockdown rules at the time.
Starmer said he was confident he hadn't breached any rules and that it was far different from the social gatherings in Downing Street that saw police issue more than 100 fines, including to Prime Minister Boris Johnson.
On Friday, Durham Police said there was no case to answer.
"Following the emergence of significant new information, an investigation was launched by Durham Constabulary into a gathering at the Miners’ Hall, in Redhills, Durham on 30th April 2021. That investigation has now concluded.
"A substantial amount of documentary and witness evidence was obtained which identified the 17 participants and their activities during that gathering. Following the application of the evidential Full Code Test, it has been concluded that there is no case to answer for a contravention of the regulations, due to the application of an exception, namely reasonably necessary work.
"Accordingly, Durham Constabulary will not be issuing any fixed penalty notices in respect of the gathering and no further action will be taken."