7. TAX EXPENSE
 
     2020 
R’m
 
  2019 
R’m 
 
Current income tax           
  Current year    538    990    
  Prior year underprovision    41    25    
Deferred income tax           
  Origination and reversal of temporary differences    (64)   (270)   
  Prior year under/(over) provision    27    (5)   
  Withholding taxes    1    95    
Total tax expense    543    835    
Reconciliation of the tax rate    %    %    
South African normal tax rate    28.00    28.00    
Adjustments for non-cash items:           
  Income not taxable – profit on sale of property, plant and equipment and investments    (0.02)   (9.83)   
  Income not taxable – partnerships    (0.89)   (0.36)   
  Expenses not deductible – impairment of intangible assets and investment    27.48    0.28    
  Expenses not deductible – interest on preference shares    1.39    1.15    
  Expenses not deductible – interest on borrowings and acquisition costs    4.16    0.48    
  Expenses not deductible – retirement benefit revaluation    4.03    0.23    
  Other2    3.18    (1.32)   
  Deferred tax through other comprehensive income    0.80    0.56    
  Prior year underprovision    8.13    0.81    
  Withholding taxes    0.20    2.57    
  Assessed losses previously not recognised    (1.84)   (1.67)   
  Effect of conversion of international tax rates to South Africa normal tax rate    18.87    1.62    
Effective rate    93.49    22.52    
2 Other include various permanent differences in foreign tax jurisdictions and South Africa for which there are no corresponding tax allowances as well as learnership allowances.

The Group has raised deferred tax on estimated tax losses of R791 million (2019: R622 million) available to offset against future taxable income. Refer note 14. Tax losses of R228 million (2019: R64 million) were utilised during the year.