Russian foreign ministry spokeswoman accused the UK of interfering in Russia's internal affairs by issuing the July sanctions against individuals thought to be involved in the mistreatment and death of Russian lawyer Sergei Magnitsky.
"In response to the unfriendly actions of the British authorities and on the basis of the principle of reciprocity, the Russian side made a decision to impose personal sanctions against 25 British representatives who are barred from entering the Russian Federation," Maria Zakharova said in a statement.
"We once again call on the British leadership to abandon an unfounded confrontational line with regard to our country."
"Any unfriendly steps will not be left without an inevitable proportionate response."
The statement did not reveal the identities of the 25 Britons.
As we reported earlier, in July, Dominic Raab, the foreign secretary, announced a total of 47 people, including the 25 Russians, had been included on a UK sanctions list.
This group was the first to have been designated for sanctions such as travel bans and asset freezes.