LONDON — After the poisoning of a former Russian spy, Sergei V. Skripal, on English soil, the British government expelled 23 Russian diplomats. Its foreign secretary, Boris Johnson, compared the upcoming World Cup tournament in Russia to the Nazi Olympics in 1936. And Prime Minister Theresa May promised there would be no place for “serious criminals and corrupt elites.”

Yet, despite the heated declarations, business continues as usual for wealthy Russians who hide and launder corrupt assets through London, a parliamentary committee said Monday in a scathing assessment that warned of “inaction or lethargy” over dirty money from Moscow.

The report, from the influential House of Commons foreign affairs committee, said there was no excuse for Britain “to turn a blind eye” while associates and allies of the Russian president, Vladimir V. Putin, “use money laundered through London to corrupt our friends, weaken our alliances and erode faith in our institutions.”

Britain’s financial and legal firms have been big beneficiaries of Russian capital flight, and London, less than four hours flying time from Moscow, is a popular destination for the country’s oligarchs, some of whom have invested in luxury property, soccer teams and other assets.