To ensure that the arm’s length principle is maintained in inter-company transactions among the subsidiaries of Abbey Limited, the following factors should be considered:

1. Comparable Uncontrolled Price (CUP) Method:
   Compare the prices charged for goods and services among the related companies with those charged in similar transactions between unrelated parties under similar conditions.
2. Cost-Plus Method:
   Calculate the cost of goods or services provided and add an appropriate markup based on industry standards to arrive at an arm’s length price.
3. Transactional Net Margin Method (TNMM):
   Ensure that the net profit margin achieved from inter-company transactions is comparable to that of similar transactions conducted by independent entities.
4. Resale Price Method:
   For goods sold between subsidiaries, the resale price to third parties should be examined. A suitable margin should be deducted to determine the arm’s length price.
5. Functional Analysis:
   Evaluate the functions performed, assets used, and risks assumed by each entity in the transaction to ensure pricing reflects their roles accurately.
6. Market Conditions:
   Consider the economic environment and market conditions in which each subsidiary operates, as these can impact pricing practices.
7. Documentation and Compliance:
   Maintain adequate documentation of all transactions and pricing methods applied to meet regulatory requirements and support transfer pricing positions in case of audits.
8. Regular Review of Transfer Pricing Policy:
   Periodically review the transfer pricing policies to align with current tax regulations and any changes in the business environment, ensuring continued compliance with the arm’s length principle.

These factors will help Abbey Limited uphold the arm’s length standard, thus minimizing tax risks and ensuring regulatory compliance in its inter-company transactions.