Travel talk this week has been dominated by overbooking. But one notable transport undertaking had plenty of spare seats.

Wednesday’s Transport Select Committee hearing in Westminster had a “load factor” of just 50 per cent. The Grimond Room in Portcullis House, across from the Houses of Parliament, was therefore significantly more civilised than a pair of recent flights on United and easyJet. The number of people on board those departures was 101 per cent of capacity, until some “re-accommodation” of surplus passengers took place.

For the future of Britain’s railways, Wednesday was an important day. The session starred the Transport Secretary, Chris Grayling, and Sir David Higgins, executive chairman of HS2 (which he pronounces, endearingly, “Haitch Ess Two”).

The pair were discussing the second stage of the planned high-speed rail line, from Birmingham to Leeds and York, and from Crewe to Manchester.

In terms of high-speed rail, the UK is almost half a century behind the elegant curves of track built across France for SNCF. French Railways began running trains à grande vitesse between Paris and Lyon in 1981, and this summer new lines are opening to Bordeaux and Brittany. HS2 gives us a chance to catch up.

The two transport heavyweights had been summoned to tackle questions on a potential conflict of interest involving a delivery partner. The rail industry has plenty of whistleblowers, of course, but this one was metaphorical rather than literal: an insider who signalled possible flaws in the procurement process.

Perhaps appropriately for a session about the railways, everyone was kept waiting for almost an hour outside the committee room. We watched as honourable members pondered and plotted their fates in the atrium below; 24 hours earlier, the Prime Minister said she would seek a snap election.

The first casualty of electioneering is, it seems, scrutiny. Besides the Chair of the committee, Labour’s indomitable Louise Ellman, only half the members were able to attend this important session. Correlation does not equal causation, of course, but I checked the parliamentary majorities of the honourable members who had attended and those who were absent.

The five who did make it were sitting on majorities of 8,000 or more. Four were Tories. The sole Labour attendee, Graham Stringer, has a 17,000 cushion in his Manchester constituency of Blackley and Broughton.

And the no-shows? Well, the Scottish representative on the committee, Stewart Malcolm McDonald, has a healthy 13,000 majority for the SNP in Glasgow South.

Since the proposed express rail link from London to the Midlands and north of England has only limited potential value for Scotland, his absence is more understandable than that of other no-showing members – such as Robert Flello, Labour MP for Stoke-on-Trent South. The line is critical for his constituents. But only 2,539 more of those voters chose him ahead of his Tory rival in the 2015 election.

The three other English MPs who failed to attend all have majorities of 6,000 or less. A cynic might suggest they are more focused on the next seven weeks than the future of the nation.

When I expressed surprise at the degree of absenteeism to one of my political colleagues at The Independent, he responded briskly: “If your job’s at risk, you don’t piss about with Select Committees.”

Voters may feel differently about a project that is expected to cost the taxpayer £56bn.

From the traveller’s (and voter’s) perspective, knowing that Parliament is keeping a close eye on the biggest UK infrastructure project of the century is comforting. As Ms Ellman says, “HS2 has the potential to deliver significant benefits. As with any investment of this size, however, it is essential that it is managed effectively.”

“We’re investing in HS2 to help free up our transport networks and bring our country together,” says the Government.