I agree that if you can afford the repayments it is not irresponsible SO LONG AS they only offer you this at a fixed rate mortgage.
Otherwise if the interest rates were to go up, there would be no affordability.If you were to earn �30,000 a year and wanted to borrow �150,000 your repaymetns would be �876.00 based on a 5% interest rate. If the rate were to go up to 6.5% the repayments would be �1024. If rates were to go up to 7.25 % (and this is the average rate over the last 10 years) payments would be �1096 - �220 more than you first signed up to.
Based on the assumption that your take home pay on �30k should be around �2,000 per month,your mortgage has just gone up by 10% of your slary!