No in my opinion
Have you done any investigation of costs in London? Its not that hard to do (google)
Transport (tube & train to Paris)?
Food?
Accommodation?
Edit
Usually for a hotel you do not get much cheaper than
http://www.travelodge.co.uk/
But will not be in prime locations (=more transport costs)
http://www.lonelyplanet.com/england/money-costs
£100=USD $140 or £72=USD $100 [
http://www.xe.com/currencyconverter/...rom=USD&To=GBP]
https://en.wikipedia.org/wiki/Big_Mac_Index (is reasonably accurate for a tourist)
http://bigmacindex.org/
Beer is expensive!