Paul Johnston was speaking during a visit to Cork today.
The EU has hit around 70% of Russian banks with sanctions while the UK has issued sanction against over 120 people and companies with ties to the Kremlin.
Prime Minister Boris Johnson says the measures are aimed at squeezing Russia from the global economy.
UK Ambassador Paul Johnston served as the Permanent Representation to NATO between 2015 and 2017.
He told RedFM News that the sanctions imposed by his government will have an impact on people in the UK and Russia:
"We don't know whether they [sanctions] will work in the short or medium term, but they need to be part of a broad based international campaign of pressure to ensure that what Russia is doing, which is barbaric and completely unjustified, that that cannot ultimately succeed. It may take time, it took time to win the Cold War. But I'm confident that because of our superior values, and our superior strengths, which are the strengths of free societies, we will ultimately prevail."
