Hello! Hope you don't think I'm stalking you (I have you as a friend on Reddit).

Anyway, it all varies on the source you use for the rate of inflation, how it's calculated (there are different ways) etc.

Although no longer updated, the National Archives offers a tool to convert the value of the currency, both pre and post-decimal, to the value of the most modern equivalent (in this case, the pound as it was in 2005). http://www.nationalarchives.gov.uk/currency/

Going back 100 years to 1915 with that, it tells us that £100 had the value of £4,306.00 in the pound of 2005. That one old penny (1d) was worth the equivalent of £0.18 in 2005 currency, and one shilling (1/-) as the value of the 2005 pound, £2.15.

However, another source (http://www.thisismoney.co.uk/money/bills/article-1633409/Historic-inflation-calculator-value-money-changed-1900.html) gives £100 in 1915 to be £10,064.21 in 2013 (you can tell the date from other drop-down boxes they give you for information), which as you can see, if quite different compared to HM Government's National Archives.

Although, even going to this source http://www.measuringworth.com/ppoweruk/ You get told that 'In 2013, the relative value of £100 0s 0d from 1915 ranges from £6,992.00 to £53,820.00', which shows how difficult it can be to work out the value of the current. Although inflation may erode the actual value of the currency, what it is able to buy can vary greatly, which is the same as today to an extent. In 2007, £350 would've bought you a new Xbox 360, but obviously now, one can buy one for much less.

What the last site does though, is give you varied statements on the possible equivalent it can have, depending on how it's calculated.

I'm not an economist, so perhaps another person could comment further on this matter.