//How do you reconcile outrageous with the cost of £8bn to maintain the state pension/s?//
You missed my sarcasm.
//NJ, is your £8 billion figure the cost of increasing by inflation or the difference between using the rate of inflation and average earnings?//
The figures I used are the estimates of around £11bn to raise it by inflation (around 10%) and about £3bn to raise by average earnings (around 3%). The third alternative of the "triple lock is 2.5%, which I assume would cost about £2.5bn.
//What is a reasonable increase and what is not will depend on one's view of what should be the going rate and by what percentage that differs from the existing rate.//
A reasonable increase would be around 20%. The UK's State Pension is among the poorest in Western Europe. On average the State pension amounts to under 50% of pensioners' incomes. This is the lowest in Europe bar the Netherlands. The percentage of government spending attributed to pensions is 4.7%. This has decreased from a recent peak of 5.2% in 2014 and is the lowest in Europe apart from Estonia and Ireland. Greece, France, Italy, Finland, Portugal and Austria all spend more than 10%. Germany 8%. The OECD average is 6.5%. There's lots more in this paper:
https://researchbriefings.files.parliament.uk/documents/SN00290/SN00290.pdf
It doesn't make particularly good reading for the UK's State pension scheme but I accept there are many variables such as the level of contributions, the number of years required to get the maximum pension and the retirement age. But the biggest bugbear I find with the State pension scheme is the total disconnection between the contributions made and the payments received. A person earning 100,000 pa will pay (at this year's rates) about 5.2 times as much NI (upon which the State Pension depends) as someone earning £20,000pa. But both will receive the same basic State Pension. And don't even start me off on the State "pensions" that have not been funded at all.