The tax system is too complicated.
The cost of collecting taxes, tax officials, form filling, accountants is prohibitive.
The system is open to preceived abuse.
Scrap all current taxes.
Introduce a tiered system of tax.
Tier1. Personal income. All personal income, from the first pound to be taxed on a graduating scale. No deductions. Investment income and such to be classed as personal.
Tier2. Business income. All business income to be taxed at a fixed amount. No deductions.
Tier3. VAT
Tier4. Additional duty, petrol, alcohol and such.