Leave campaigners have hit back after Tony Blair suggested "rational" voters would listen to US president Barack Obama's warnings about the dangers of Britain leaving the European Union.
In an outspoken intervention in the referendum campaign, the former prime minister said he believed the country would "do the sensible thing" and vote to stay in.
Mr Blair also insisted the wave of immigration from eastern European countries that took place under his premiership had not been a problem for the country because the migrants contributed more in taxes then they took in benefits.
But Brexit campaigners attacked the ex-Labour leader for consistently failing to secure a good deal for Britain during his time in No 10 and accused him of "irresponsibly" opening up the UK's borders.
It comes as David Cameron prepares to be quizzed on the June 23 referendum by the powerful Commons Liaison Committee.
Chairman Andrew Tyrie said the Prime Minister would face "careful scrutiny" in the 1hr 30min session later.
"The Prime Minister is uniquely well placed to provide this evidence," he said. "The decision to call the referendum was his. He led the renegotiations. So it is his views and explanations that matter most, and are most worthy of careful scrutiny."
Mr Obama used a visit to London last month to warn that Britain would be at ''the back of the queue'' for American trade deals if it quit the EU.
After talks with Mr Cameron, he insisted the UK would not be able to strike a free trade deal with the US ''any time soon'' because Washington's focus would be on reaching agreement with Brussels.
The comments sparked a furious backlash from the Brexit camp, which claimed the president was "doing the bidding of Cameron" and accused him of "hypocrisy" for intervening in the British campaign.
But Mr Blair said Mr Obama's views "count" and it was "important" that voters know what he thinks.
In an interview for Bloomberg TV in Los Angeles, he said: "When you look at the polls, they're pretty evenly matched. But my best instinct about this is that the country will do the sensible thing and stay in the EU.
"If we were to leave it would put a level of economic insecurity into the ordinary family household that I think most people would think is a foolish risk to take. But I have to say I look at politics round the world these days and it's in an unpredictable state.
"If you're rational, the view of the president of the most powerful country in the world and our biggest ally should matter. When someone like President Obama comes, I think it's important we know his view. It does count.
"Personally, I do not feel that the immigration from eastern Europe was a problem for Britain. I think those people contribute far more in taxes than they ever take in benefits. They're hard-working people, they're good members of our community. And the benefit of having eastern Europe in the EU is enormous."
A Vote Leave spokesman said: "Tony Blair consistently failed to get a good deal for Britain from the EU, squandering our rebate and irresponsibly opening up our borders.
"There's nothing rational about giving Brussels £350 million a week only to allow it to undermine our democracy, our economy and our borders. The sensible thing is take back control on 23 June and Vote Leave."