The US experience of low-price shale gas will not be replicable in the UK. The reason the cost of gas has fallen through the floor there is that the US has experienced a glut of gas as more and more producers piled into the sector. Costs across the industry fell through the floor as drillers, pipeliners etc poured in and competed to get gas to market and buyers were able to push prices down due to oversupply.
It is almost impossible for the same dynamics to occur in the UK or elsewhere in Europe - environmental regulations and lack of a "small co" oil/gas sector mean it is much more likely to mirror the Australian unconventional gas industry - all investment and operations being run by a few multinationals, with projects underwritten by long-term contacts.
The rationale for seeking more gas is also different. In the US gas had an enormous ready-made domestic market, with limited import-export capability ensuring prices were not linked to international prices. The UK is part of a gas trading hub - so unless the government mandates that all shale gas has to go to domestic use, it will be priced at close to export parity. There is no driver for producers to sell at US prices.
The US has gone from a net importer of gas and (actually quite contrary to what some have said) is beginning to allow limited exports of gas. The simple reason is that gas sells for maybe $4/GJ in the US, vs $9+ in Europe and more like $14 in Asia. With shipping costs maybe $1-2 depending on the market, its an absolute no-brainer to export as much as possible, with Asia the preferred market (particularly as Asia already has significant regasification facilities).
US gas is so cheap that its even displaced coal for electricity generation. This has also had the effect of reducing CO2 emissions from electricity in a country with no carbon pricing. By contrast, Germany has accepted the fact that coal is much cheaper in Europe and is building significant coal generation capacity in recognition of excessive electricity prices, despite the hit on future CO2.
Whether fracking is environmentally safe is open to question, but the chances of it leading to falling gas prices for UK consumers is negligible.
