These are the key recommendations - and the analysis by The Independent.
What's the problem?Mr Johnson, the third Conservative prime minister in the past 11 years, asked Sir Peter Hendy to look at the quality and availability of transport infrastructure within the UK and where future investment should be targeted.
In particular, the focus is on "specific transport projects that could improve connectivity" - and assessing "their feasibility and potential impact on economic growth, social cohesion and quality of life". The PM has plenty of history with Sir Peter, since he was Commissioner of Transport for London while Boris Johnson was mayor. Sir Peter's assessment looks at rail, road and air connections, as well Mr Johnson's plan for a fixed link between Scotland and Northern Ireland.FREE WEEKLY NEWSLETTER
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It appears, though, that the prime minister has already formed some strong views on some of the issues.
What's on the rail agenda?The main focus is on accelerating rail links between England and Scotland through upgrades to the West Coast and East Coast Main Lines. There is also interest in boosting rail capacity in the Bristol and southeast Wales area, and upgrading rail connections between North Wales and the key conurbations in England of Merseyside and Greater Manchester - as well as connections with the High Speed 2 (HS2) line from London to Birmingham, Crewe and beyond.
Boris Johnson also asks: "Why are we stopping HS2 in England?" The reason is: the benefits in terms of capacity and market demand quickly disappear north of the Liverpool/Manchester/Leeds axis.
The prime minister postulates: "We don't need a new line; with some bypasses, better track and signalling, as Sir Peter believes, we could run services from Glasgow to London in about 3 hours." But Darren Caplan, chief executive of the Railway Industry Association, is keen that existing projects are not overlooked.
He says: "Rail has a vital role to play in the UK's economic recovery from coronavirus and in achieving net zero by 2050, but to do so it needs certainty on planned rail schemes, like HS2 Eastern Leg, Northern Powerhouse Rail and the Midlands Rail Hub."
What are those three schemes, exactly?The HS2 Eastern Leg would run northeast from the West Midlands to Sheffield and Leeds.
The government has not yet formally given the branch the go-ahead, and there are concerns that the brand-new high-speed line could be downgraded to a series of improvements to existing rail infrastructure. Northern Powerhouse Rail intends to add a new line from Liverpool to Manchester airport and another from Manchester to Bradford and Leeds, while improving existing lines serving Sheffield, Hull and Newcastle. The Midlands Rail Hub is a plan to accelerate travel by train and increase capacity across a wide area from Cardiff, Bristol, Hereford and Worcester via Birmingham to Leicester, Derby and Nottingham.
The prime minister correctly points out: "It's currently quicker to get a train from Cardiff to Paris than from Cardiff to Edinburgh." The 108 miles from Cardiff to Birmingham takes 2 hours (15 minutes longer than the 150-mile trip to London), while Birmingham-Edinburgh is 4 hours - about 50 per cent longer than London-Paris. It is not clear that planned or contemplated improvements will equalise the journey times.
How will roads be improved?The review - and the prime minister's opinion - are much clearer. The targets are:
- A1 between Newcastle and Edinburgh, "where average delays are higher and average speeds lower than other non-motorway sections of the A1". It would be expanded to a dual carriageway. - A75 between Gretna (near the top of the M6) and Stranraer in southwest Scotland. "It is a single carriageway," says the prime minister. "For 95 miles." It is likely to be expanded to a dual carriageway.
- M4 between England and Wales: increasing capacity. The tensions and blame games between the UK government and other nations are clear from an exchange on the M4 improvements. Mr Johnson says: "The Welsh Labour government managed to spend GBP144 million on a plan for relieving congestion (I kid you not) and then mystifyingly junked the scheme."
But a spokesperson for the economy minister in Wales, Ken Skates says: "Congestion on the M4 has in part been caused by the UK government's own historic underinvestment in areas like rail infrastructure. "The UK government should spend more time focusing on what they can do to help deliver the Burns plan [to reduce congestion on the M4 in south east Wales] and addressing the chronic underfunding they have overseen in rail that has led to congestion in the first place." All the evidence shows that increasing capacity triggers an increase in traffic.
There is no mention of road pricing, which many analysts see as the best way to manage congestion. The transport expert Thomas Ableman says: "In the month that the government froze fuel duty for the 10th consecutive time, it's disappointing the review doesn't talk about the role the government has to play in incentivising different travel choices, especially with a nationwide road pricing scheme." Heathrow passengers queuing for up to six hours, chief exec Emma Gilthorpe warns
And in the skies?"I want to cut passenger duty on domestic flights so we can support connectivity across the country," says Boris Johnson. When air passenger duty was first introduced by Conservative chancellor Ken Clarke in 1995, the GBP5 flat rate for short-haul flights was charged on only one leg of return domestic trips.
But under European Union rules the UK was later obliged to apply it to both flights. A year ago the UK's then-largest regional airline, Flybe, collapsed, dramatically reducing the number of domestic links. Many of them have been filled by Loganair, Eastern Airways, Aer Lingus and easyJet, but some gaps remain.
Domestic airlines have long complained about Air Passenger Duty (APD), which adds GBP13 to a one-way flight and GBP26 to a return trip within the UK. The prime minister says: "It seems wrong that someone flying from Belfast to London and back pays more UK tax than someone flying from Dublin to London and back." Derek Provan, chief executive of AGS Airports - owner of Aberdeen, Glasgow and Southampton, says: "Boris Johnson's desire to see a reduction on what is a regressive tax to passengers and the industry is welcome news.
"The world has changed dramatically as a result of Covid-19 and the routes and services that play a critical role in supporting our economy have been devastated. "A reduction in domestic APD is a welcome first step towards rebuilding the UK's domestic connectivity as we work towards the safe return of international travel and getting the economy moving again." But Mr Ableman says: "The interim conclusions hint heavily towards a cut in Air Passenger Duty, which would catastrophically harm the UK's leadership on climate change in the year we host COP26."
The 26th UN Climate Change Conference is due to be held in Glasgow in November.
What routes might return if domestic APD were cut?The Independent asked the airline schedule analyst Sean Moulton to identify the five key Flybe UK domestic routes that have not been filled.
He nominates: Cardiff-Edinburgh Cardiff-Glasgow
Belfast-Doncaster Exeter-London City Birmingham-Newquay
Of these, it appears Sir Peter has only Belfast-Doncaster in mind. He says he is considering ways for "better air links to England to and from Northern Ireland and Northern Scotland". Crucially, he also said that he would be making recommendations on "the appropriate rate of Air Passenger Duty for journeys not realistic by rail".
In other words, links such as Exeter-London City would not get a discount. But it appears Mr Johnson has other ideas.
What about that bridge or tunnel between Scotland and Northern Ireland?
Sir Peter skilfully moves the project to connect the two nations beyond his remit by asking a couple of engineers to give it their professional consideration - in the expectation that they will declare MrJohnson's plan, though theoretically desirable, to be extremely challenging logistically and financially. Mr Ableman said: "When it was announced last year, the Union Connectivity Review looked like a fig-leaf for Boris Johnson's unwanted vanity projects, so it's encouraging to see the crazy bridge to Northern Ireland shunted out of the review. "Boris's time as mayor of London showed his capacity for such projects to be almost unlimited, spawning the Garden Bridge, the Boris bus and the cable car to nowhere.
"As interpreted by Sir Peter Hendy, the review is turning into a more rational review of transport connectivity both between and, crucially, within the UK nations."