Isn't it funny. Every business case ...

is called robust;

robustly justifies every kind of expenditure from spending £1 billion of public money on 14 Kms of tramline to duplicate a bus route in Edinburgh in 2014;

to spending nearly the same but, this time, private money on the M6 Toll for 43 Kms in 2003;

to splashing out £17.6 billion of public money on 117 Kms Crossrail;

to justify spending £44,000 per metre to extend Edinburgh's £1 billion tram line to Newhaven to replace buses;

to justify spending £44,000 per metre to convert our ready made, but they forgot the trains and stations, 120 Kms mainline "of national strategic significance" into a piddling little shuttle tram line on two short, middle sections, totalling 6.7 Kms.   

"The latest work to refine the scheme and the efficiencies to be developed within the Midland Metro Alliance give a good level of confidence that the project can be delivered within the current funding envelope (SELF: of £44,000 per metre, times 11 Kms.  Eleven times the cost per kilometre of the second attempt at returning trains between Wolverhampton and Walsall.  The first attempt was a failure, last decade!)."  Report to WMCA Investment Board on 11 March 2019

"the scheme has a benefit to cost ratio of 2.03:1."      

Every business case comes up with a great Cost Benefit Ratio that compels massive expenditure, eg to dismantle/destroy the tram network and to rebuild it on the road and railway networks a few decades later.  This is called high Value for Money when it is 2.03:1.  In other words, you double your money.  Therefore, whatever you pay up front, you get more than double that back in destroying yet another urban and intercity railway line, in the case of trams taking over the UK's one and only mothballed mainline.

"As part of the arrangements for the transfer of part of the abandoned South Staffordshire rail corridor (SELF: anachronistic, out of date, inaccurate name DfT now call 'The Black Country Railway') to Metro an agreement with Network Rail is being negotiated to ensure passive provision is made within the Metro works for future rail service use of the route. Implementation of future rail services will be subject to consultation between Network Rail and WMCA and appropriate powers and funding being secured." 

All this, when there is never a business case to cut public spending on the Police, the NHS/social care or education to pay for all this largesse.  "Don't worry your little head over it all, Tim.  You know that you will get back double whatever the final cost is because cost benefit analysis tells us so.  It is another of Mrs May's magic money tree tricks."

The money is always found for the flash, the glamorous, the most prestigious projects to hasten Attenborough's "collapse of civilisations" and "the extinction of much of the natural world" warnings from COP24 in Poland in December 2018.