Recliner wrote:

Roland Perry wrote:
In message

-sept ember.org, at 20:27:59 on Tue, 26 Apr 2016, Recliner
remarked:

I don't believe that absurdly low cost figure. In 1992 terms, the
cost of the full Piccadilly line extension, including the four
stations, was probably well over £250m, maybe closer to £500m.

If you don't accept the contemporaneous figure of £26m build cost
when it opened, then other discussion is futile. Can you come up
with a better figure from the archives - if you do we can resume
talking about the return on investment.

As you well know, it wasn't a contemporaneous figure. It was an
absurdly low estimate, from an aviation magazine, from years earlier,
that was not only many times too small for even the original simple
1977 extension, but also couldn't have taken into account the
eventual scope of the project, with four stations rather than two,
and the extended tunnels to T4 and T5.

£26m is in the right ballpark. According to Hansard from 15 Dec 1976

Mr. Sillars asked the Secretary of State for Transport what is his
latest estimate of the Government share of costs associated with
building the Piccadilly underground line extension to Heathrow Airport.

Mr. William Rodgers - My Department contributed 25 per cent. of the
total expenditure of £18.5 million incurred up to 31st March 1975.
Expenditure since then, estimated at £7.2 million to 31st December
1976, qualifies under the Local Government Act 1974 for transport
supplementary grant at the rate of 70 per cent. The total cost of the
work outstanding at 31st December 1976 is estimated to be £3.6 million.

http://hansard.millbanksystems.com/w...761215_CWA_194

So the total cost was approx 18.5 + 7.2 + 3.6 = 29.3 million.

Using RPI, that would be around £220 million in todays money.

Peter Smyth