London’s mayor says doubts about there being 70,000 ‘moderate’ fighters means allies cannot be picky if they want to defeat jihadis

Britain and its allies should accept that Bashar al-Assad’s forces are best placed to lead a ground assault against Islamic State in Syria because David Cameron’s claims about 70,000 moderate opposition forces are “exaggerated,” Boris Johnson has said.

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In remarks that may be seized on by Labour opponents of the airstrikes in Syria, Johnson says that “Assad and his army” may be the allies’ best chance of removing Isis because the 70,000 figure includes groups that are ideologically little different from al-Qaida.

The prime minister faced intense pressure in the House of Commons last week after claiming that 70,000 “moderate” fighters in Syria are prepared to join the UK and its allies in attacking Islamic State. Jeremy Corbyn questioned the figure as he spoke of a lack of “credible ground forces”.

Johnson waded into the row by saying that Britain and its allies, which cannot overthrow Isis without ground forces, cannot be picky about their allies in light of doubts over the 70,000 figure.

London’s mayor wrote in the Daily Telegraph: “We have the estimated 70,000 of the Free Syrian Army (and many other groups and grouplets); but those numbers may be exaggerated, and they may include some jihadists who are not ideologically very different from al-Qaida. Who else is there? The answer is obvious. There is Assad, and his army; and the recent signs are that they are making some progress.”

The remarks by Johnson, who is a member of the political cabinet, are likely to irritate the prime minister who is facing cross-party questions about his claim, made last month, about the 70,000 opposition fighters. The prime minister told MPs: “We believe that there are around 70,000 Syrian opposition fighters, principally of the Free Syrian Army, who do not belong to extremist groups, and with whom we can coordinate attacks on Isil [Isis].”

Julian Lewis, the Conservative chairman of the Commons defence select committee, has led the charge against the 70,000 figure on the grounds that it is likely to include Islamist fundamentalists who will not be minded to help allied countries. Lewis told the Commons last week: “Instead of having dodgy dossiers we now have bogus battalions of moderate fighters.”

In his article, Johnson challenged Downing Street to acknowledge that Isis would only be defeated if the allies join forces with Assad and President Vladimir Putin. Highlighting the news that Assad’s forces are close to the historic centre of Palmyra, he writes: “Am I backing the Assad regime, and the Russians, in their joint enterprise to recapture that amazing site? You bet I am. That does not mean I trust Putin, and it does not mean that I want to keep Assad in power indefinitely. But we cannot suck and blow at once.”

Johnson backed up his argument by citing Winston Churchill’s reaction to the Nazi invasion of the Soviet Union. “When Hitler invaded the Soviet Union, Churchill decided to qualify his lifelong hatred of communism. ‘If Hitler invaded Hell,’ said Churchill in 1941, ‘I would make at least a favourable reference to the Devil in the House of Commons.’ And as he foresaw, it was the Russians who did the most to help us win the war.”