Primary legislation introduced Part 6A into the Taxation (International and Other Provisions) Act 2010 which contains detailed rules which implement BEPS Action 2 recommendations.  The main operative rules are contained in the following chapters:
Chapter 3: Hybrid Financial Instruments (recommendation 1)
Chapter 4: Hybrid transfer deduction/non inclusion mismatches (recommendation 2)
Chapter 5: Hybrid payer deduction/non inclusion mismatches (recommendation 3)
Chapter 6: deduction non/non inclusion mismatches relating to permanent establishments
Chapter 7: Hybrid payee deduction/non inclusion mismatches (recommendation 4)
Chapter 8: Multi national deduction/non inclusion mismatches (Branch recommendation 2)
Chapter 9: Hybrid payer double deduction rules (recommendation 6)
Chapter 10 Dual territory double deduction rules (recommendation 7, Branch recommendation 4))
Chapter 11 imported mismatches (recommendation 8, Branch recommendation 5)