After several Western leaders all but called Russian president Vladimir Putin a liar for his statements on Russian actions in Ukraine, Putin decided to leave the G-20 Summit early and not participate in the official luncheon at Sunday.

The fact is, no one believes Putin's denials of Russian non-involvement anymore.  And his provocative acts – such as sending several warships to Australia – are not impressing anyone.

Telegraph:

The Russian president is reportedly planning to leave the summit early on Sunday and miss its official lunch in response to repeated criticism from western leaders.

The move comes after Tony Abbott, the Australian Prime Minister, threatened to "shirt front" Mr Putin - a form of physical confrontation. Stephen Harper, the Canadian Prime Minister, told Mr Putin: "I guess I'll shake your hand, but I'll only have one thing to say to you - get out of the Ukraine."

Mr Cameron told Mr Putin that he is at a "crossroads" and could face further sanctions after the pair held "robust" discussions on Ukraine.

During a tense 50 minute meeting Mr Cameron warned that Russia is risking its relations with the West and must end its support for Russian separatists.

Mr Putin denied that Russian troops have entered Ukraine and claimed that he is prepared to accept a ceasefire and stop the flow of Russian weapons across the border. He also said that he is prepared to recognise Ukraine as a "single political space".

Mr Cameron is said to be "realistic" about Mr Putin's comments after he previously broke pledges to end Russian action in Ukraine.

The meeting at the G20 summit in Brisbane, Australia, follows a tense build up in which Mr Cameron compared Russia to Nazi Germany.

Tensions escalated further when Russia stationed a fleet of warships off the coast of Australia in an apparent show of strength ahead of the summit.

In interviews hours before the meeting, Mr Cameron suggested that he cannot trust Mr Putin and described Russia's decision to send a fleet of warships to Australia as "international machismo".

Asked if he trusts Mr Putin, the Prime Minister told ITV News: "I take people as I find them. The sad thing is that to date undertakings given in the Minsk agreement have not been followed but the right thing to do is to continue to engage.

"So far we haven't seen his actions follow up the statements that he's given on previous occasions.

"The point is and the reason for meeting is that this issue matters and it's very important Russia understands what's at stake and gets a very clear message.

"There's a real choice here, there's a different and better way for Russia to behave that could lead to an easing of relations, but at the moment he's not taking that path."

Putin can lie the way he does because he doesn't have to convince anyone outside Russia that he's telling the truth.  He is dismissive of NATO and apparently feels that no Western leader is his equal.

As long as the Russian people believe and support him, Putin will feel no compunction in telling bigger and bigger lies.  The fiction that Russian troops aren't in Ukraine will continue and no amount of proof supplied by the government of Ukraine that contradicts the lie will cause Putin to deviate one inch from promoting his propaganda.