Why taxation matters in this election
Taxes are the main way the government raises money and therefore directly increasing them, or reducing existing tax reliefs, is one way of bolstering government finances. It is likely that whoever forms the next government will make changes to the existing tax regime to help it reduce public spending and meet its fiscal targets.
Taxation is a partially devolved power in Scotland.
What's at stake?
Just three taxes: income tax, national insurance contributions and value added tax (VAT) provide the bulk (three-fifths) of the government's revenue, meaning changes to any of these are likely to have the biggest impact and are therefore most likely to be targeted.
All parties have said the impact of any changes they make should affect those who are better off.
But the focus is likely to be on how this is defined. Wealthier people already pay more income tax and while the personal allowance - the point at which any income tax starts to be paid - has increased since 2010 more people have also been brought into the higher-rate tax band of 40%.
The high cost and shortage of housing in the UK means that housing-related taxes are also a hot issue, with a mansion tax on properties worth more than £2m or a reform of the council tax system both being suggested to combat problems of inequality in the market.
Wide demand for a reform of the business rates system - the tax firms pay on commercial buildings - as well as widespread criticism of tax avoidance by multi-national firms and wealthy individuals means these issues will also be in focus.
What are the numbers?
Taxes are expected to raise £622.9bn in 2015-16, according to the independent think-tank, the Institute for Fiscal Studies (IFS). That is equivalent to roughly £11,800 for every adult in the UK, or £9,600 per person.
A quarter of income tax comes from 0.5% of the adult population and around half comes from 3% of adults in 2014-15.
The number of higher and additional rate taxpayers has increased from 674,000 in 1979-80 to 3.3 million in 2010-11 and is expected to be five million in 2014-15.
What the politicians won't be saying
That taxes will rise. While none of the main political parties have suggested any significant tax rises, the IFS's research shows that every general election since 1992 has been followed by net tax rises of more than £5bn a year (in 2015-16 terms).
What has happened since 2010?
- Main rate of VAT increased from 17.5% to 20%
- Personal allowance increased from £6,475 to £10,600
- Higher rate tax threshold decreased from £43,875 to £42,385
- Corporation tax reduced from 28% to 20%
- Local authorities given incentives to freeze council tax rates
- Fuel duties cut and frozen at 57.95p per litre since 2011
- Inheritance tax threshold frozen at £325,000
- Child benefit, a tax-free payment aimed at helping parents cope with the cost of bringing up children, reduced in families where one parent earns more than £50,000 a year and stopped in families where one parent earns £60,000 a year
What the experts say
"It would not be surprising if an incoming government were to contemplate raising taxes following the May 2015 general election. Nor would such a scenario be at all unusual" - IFS
"Every party avoids talking about the taxes they plan to put up. They will tell us about the little tax rises, but not about the bigger stuff" - Bill Dodwell, head of tax policy at Deloitte