It is almost classic chaos theory, riots in the street in one country such as Egypt can affect the price of houses in UK. Seems strange but it really is possible, here is why.
Instability in Egypt affects the Middle East region and in turn this could affect oil prices. Already the ripples are being seen in the currency markets as currency traders and investors mark down the higher risk currencies. If investors see a threat to future oil prices then prices will most likely increase.
Any increase in oil prices will impact economies and in particular the UK economy which is already experiencing an inflation upturn. If UK inflation increases too far then the pressure on the Bank of England to raise base rates will grow. And with increased interest rates it will make the cost of house purchase higher, thus impacting on UK property prices.
So far we have just used the oil example, but other commodities are at risk of price increases, one major example is wheat prices. Any increases in commodities will again feed into higher inflation.
The bottom line is the stability in Egypt and the Middle East is key for the UK economy, and most especially whilst the UK is experiencing its own domestic issues due to the extraordinarily high level of national debt.