Will the bitter row over a proposed new runway for Heathrow Airport prove to be the undoing of Boris Johnson, possibly leaving his reputation in tatters and wrecking his (admittedly disputed) ambitions to become leader of the Conservative Party?

Johnson has adopted what many would describe as an “over my dead body” approach in his fervour to prevent an extra runway at Heathrow.

So why was he not present at the key exchanges in the Commons last week over this white-hot burning issue?

It can’t have been cowardice – Johnson is not made like that. No, it is more likely clever-clogs Boris wanted to avoid having to attack his own government in public.

So, what was his excuse for being awol? He claimed, through his office, that he had a prior and long-standing engagement as Mayor of London, chairing a board meeting of Transport for London.

Important though that engagement might be, I cannot but feel it is a flimsy excuse. Not only (I would have thought) should Parliament have come first in his activities on that day, but he should also have been there to wave the flag and speak out on behalf of his constituents.

His constituency is Uxbridge, in the West of London, an area which would be hugely affected by any such major developments at Heathrow. So you could argue he has let his constituents down for not being present to underline his views, which are also surely the views of most of his voters in Uxbridge.

Johnson is probably relying on the likelihood this lapse on his part will quickly blow over and soon be forgotten. That, I am afraid, will not happen. This row will run and run, and at some point Johnson will have to come out hot and strong in the Commons, even if it does seriously damage his prospects of leading the Conservative party and possibly, at some stage, being handed the keys to 10 Downing Street.

But not being there to fight his corner on behalf of his constituents could be even more damaging than that.

You can already hear the anguished howls of protest at Chancellor George Osborne’s Budget proposal to put an end to cheap rents for council house tenants who earn over £40,000 a year in London and £30,000 a year elsewhere in the country.

It is said this will affect 340,000 people and will save an estimated £250 million a year as part of the Chancellor’s bid to cut the welfare bill by £12 billion.

But those who protest about the removal of this and other welfare perks from those who do not really need them, should instead spare a thought for the taxpayers who in their thousands, if not millions, are now helping subsidise people that are earning more than they are. The unfairness of that is palpable and the Chancellor is right to call a halt to it.

David Cameron can look forward to – if that is the right expression – an all-out war with the Scottish Nationalists over the Government’s plan to give English MPs a veto over legislation which affects only England. In other words: “English votes for English laws”.

The move has been denounced by the SNP as “a constitutional outrage” and by Nicola Sturgeon, the SNP leader, as “a shambles”.

Since their idiotic schoolboy antics at the very start of the Parliament, the Nationalists have been relatively well-behaved since then – if that does not sound too patronising.

But now there is clear evidence the Tartan Army, which won almost every parliamentary seat north of the border, are planning to arm themselves to their political teeth to storm the Government’s barricades and quash this proposal. They could have the support of other opposition parties in this endeavour...

There are already issues relating purely to Scotland on which English MPs have no say.

So this plan, to most fair-minded people outside the political whirlpool, seems simply the right and just thing to do.

It is certainly not worthy of the exaggerated and bombastic language being used to attack it.

Professor Tony Travers, of the LSEondon School of Economics, suggests the Palace of Westminster’s renovations provide a good opportunity to move Parliament out of London – to the small Yorkshire town of Hebden Bridge, near the border with Lancashire.

But Sir Bernard Ingham, who was Margaret Thatcher’s press chief and is Hebden Bridge’s most famous son, does not agree. He said: “This convinces me that academics are completely and utterly barmy. Where on earth in Hebden Bridge, except possibly the Picture House, and that would be hopelessly overcrowded. Could you accommodate 650 MPs and all the hangers-on? Totally crackers.”

Sir Bernard was never one to mince his words.