Lammy has been fined £5,000 by the Information Commission after instigating calls that urged people to back his bid for London mayor, before Sadiq Khan won Labour's nomination.
The Information Commission is warning other political campaiginers to keep within the law after fining the Tottenham MP.
Lammy instigated 35,629 calls over two days, playing a recorded message that urged people to back his campaign to be named the Labour party candidate for London mayor.
Under the rules, calls that play a record message must only be made to people who have given the organisation their permission to receive this type of call.
The calls were made in August 2015 using contact details of party members provided by the Labour Party. Lammy did not make the additional checks necessary to ensure he was able to contact the people with recorded messages.
Information commissioner Christopher Graham said:
The rules apply to political groups canvassing for votes in the same way they apply to salespeople offering a discount on double glazing. If you want to call someone in this way, you must follow these rules. Lammy did not, and that is why he has been fined.
It’s not good enough to assume the people you’re contacting probably won’t mind. The law requires you to have permission before making calls with recorded messages. And if the law isn’t followed, the regulator will act.
So the commission is now urging political parties to take note of the rules in the upcoming EU referendum, devolved assembly elections and English local government elections.