Cameron picking up where Blair left off

A strong sense of deja-vu will likely hang over Canberra when British prime minister David Cameron addresses a special joint sitting of parliament.

The last time a British leader spoke in Australia's parliament was 2006, when Tony Blair warned of the "immediate threat" of Islamic extremism and the global ideology at war with our way of life.

He praised Australian and British troops fighting the west's "war on terror" in Afghanistan and Iraq but acknowledged there were those who disagreed with the merits of the conflict.

"When the terrorists struck, Britain and Australia reacted in the same way. We did not turn on Muslims. We united against terrorists," he told parliament.

Eight years on some things haven't changed.

Australia and the UK are both committed to tackling Islamic terrorists, this time not al-Qaeda but their spawn in Iraq and Syria under the black banner of the Islamic State.

Both nations also face a renewed threat of homegrown terrorism, with civilians departing for the battlefields of the Middle East to join jihadists.

When Blair made his speech in 2006 the British were still mourning those killed less than a year before in the London bombings.

Australia too was reeling from a second wave of bombings in Bali just seven months earlier.

The threat is different today but similar themes are bound to echo during Cameron's speech on Friday.

The conservative prime minister will also join Tony Abbott at the Australian War Memorial, before the pair fly to Brisbane ahead of the two-day G20 leaders summit.