The man responsible for Britain's cyberdefences says a suspected hacking campaign to influence the US election could inspire attacks on the UK.
Ciaran Martin, chief executive of the National Cyber Security Centre, said it may have created "a perception that this is a successful model".
He said GCHQ took measures to protect the 2015 UK election against hacking.
Multiple investigations have been launched into claims that Russia sought to interfere with the US election.
Thousands of emails were hacked from officials of the Democratic National Committee, as well as Hillary Clinton's campaign chairman John Podesta, and leaked on the internet through several sites including Wikileaks.
Neera Tanden, a former close aide of Hillary Clinton whose emails were among those leaked, told BBC Newsnight the hacking campaign may have made the difference between Mrs Clinton winning and losing the presidential race.
She said: "I believe the leak was a large part of why Hillary had real problems with millennials [people born in the 1980s and 1990s] which is why she did not hit her targets in the three states [Michigan, Pennsylvania, Wisconsin]…. The truth was that at high points of the campaign before the leaks, Hillary was hitting 60% of millennials. On election day she was hitting 53, 54, 55%."
Although US intelligence officials have publicly blamed Moscow for hacking the Democratic National Committee computers, Mr Martin would not comment on whether UK intelligence agencies had seen evidence of Russian involvement in hacking in the US.
He stressed that the threat of countries attempting to influence political outcomes through hacking should not be overstated. "States undertake cyber-attacks for all sorts of different reasons.
They undertake it sometimes for commercial and economic advantage, they undertake it for commercial espionage. They undertake it for political espionage. And it may be the case that states are undertaking cyber-attacks in order to achieve outcomes in influencing and propaganda."
He added: "There may be a perception now that this is a successful model for intervention in a society such as ours and those of our allies. And clearly that's something we need to be prepared to deal with."
He also said he "fully endorsed" comments by Germany's domestic intelligence chief stating that there was already evidence of attempts to influence next year's German election by hacking.
You can watch Newsnight's report on hacking at 22:30 GMT on 15 December catch up afterwards on iPlayer