Marina Litvinenko arrives Jan. 21 to attend a news conference at her lawyer's office in London after receiving the results of the inquiry into the death of her husband, Alexander Litvinenko. The former KGB officer was poisoned in 2006 with radioactive polonium-210 in the United Kingdom, having fled Russia after criticizing President Vladimir Putin. (Carl Court/Getty Images)

The British government has been accused of responding too weakly to an inquiry that concluded that Russian President Vladimir Putin “probably” ordered the killing of Alexander Litvineko.

Shortly after the inquiry was released Thursday, Theresa May, the home secretary, said that she would seek a European arrest warrant for Andrei Lugovoi and Dimitry Kovtun, the two chief suspects accused of poisoning Litvinenko at a posh London hotel by lacing his tea with a radioactive substance.

May also said that the assets of the two men would be frozen, and summoned the Russian ambassador to the Foreign Office to express the government’s “profound displeasure” at what she said was an “unacceptable breach” of international law.

Expressing “profound displeasure” was “not enough,” said the Times of London in its editorial. The paper also wondered whether the two chief suspects even had any assets in the U.K. to freeze.

“Insisting there should be no diplomatic fallout amounts to an admission that Britain can be cowed,” said the Guardian newspaper, which suggested “Europeanising” the issue with the European Union, freezing assets and slapping travel bans on specific Russian officials.

The paper’s columnist Simon Jenkins, who argued against beefing up existing sanctions against Russia, nonetheless noted that May’s response was “certainly puzzling.”

“A Commons rebuke and a summoning of the Russian ambassador (for “tea”?) in the Foreign Office is hardly retaliation. Moscow’s reaction was one of hilarity. Surely we could send a drone over a Russian embassy somewhere and drop a note of protest?” he wrote.

“It’s just cowardly folly to appease this thug,” ran one headline in the Daily Mail.

Commentators have said that the U.K. is not flexing its muscles for many reasons, including a desire by the West to continue to work with Russia on issues like ending the conflict in Syria.

But not everyone agreed that it was a good enough reason.

“Diplomats will argue that British-Russian relations are too complex to be subordinated to a single dispute, but the Litvinenko case and the broader relationship are linked. Mr Putin and his proxies have been emboldened to invade foreign countries in no small part because they have been allowed to act with impunity to settle personal vendettas in foreign capitals. London is one of their favourites,” said the Times of London.

British Prime Minister David Cameron has said that he hasn’t ruled out further punitive action, but has suggested a desire not to plunge already cool diplomatic relations into the deep freeze.

"There's no doubt that when it comes to Syria, we need all of the players, whether it's Saudi Arabia or Iran or Russia. Everyone needs to be involved,” he told Al-Jazeera TV on Friday.

He added: "Obviously, we have real difficulties with our relationship with Russia because of what has happened, and it's right that we take the action we announced yesterday. But when it comes to Syria, difficult as it is, we have to discuss this issue with them.”

Alexander Litvineko’s widow, Marina, has called for all Russian intelligence agents to be expelled from the U.K. and for targeted sanctions and travel bans for those responsible for her husband’s killing.

And she’s still hopeful. In an interview, she said that the British government may ultimately respond more robustly, but appreciates that it may take time as the government considers its options.

“I’m keen for the people who were involved in this crime to take responsibility,” she said.

But she’s fought tirelessly for nearly 10 years for conclusive answers to her husband’s death, and said that she didn’t expect instant action.

“It needs time,” she said. “In this situation, I’d like to show I’m not pushing the government, I’m giving them time to realize what they need to do.”

But, she added: “I don’t want to wait for another 10 years.”