Forward Looking Statements – Caution Advised

1. Forward Looking Statements – Caution Advised • Certain statements in this presentation are forward-looking and are made in reliance on the safe harbour provisions of the US Private Securities Litigation Reform Act of 1995. These statements include, without limitation, those concerning: BT's plans for transformation of its networks; benefits to customers of the 21CN programme; key milestones and expected timetable for delivery of 21CN; and the benefits in relation to, for example interconnect, convergence and broadband. • Although BT believes that the expectations reflected in these forward-looking statements are reasonable, it can give no assurance that these expectations will prove to have been correct. Because these statements involve risks and uncertainties, actual outcomes may differ materially from those expressed or implied by these forward-looking statements. • Factors that could cause differences between actual outcomes and those implied by the forward-looking statements include, but are not limited to: material adverse changes in economic and financial markets conditions in the markets served by BT; supplier arrangements; future regulatory actions and conditions in BT’s operating areas; technological innovations; developments in the convergence of technologies and the anticipated benefits and advantages of new technologies, products and services, including broadband, not being realised.

2. Migration Provisioning:Interconnect Routes – DLE to NGSRon Riches The purpose of this presentation is to outline to Communications Providers BT’s view of: How BT will manage the allocation of slots for route migration Fallback for DLE to NGS migration

3. Interconnect Route Migration:Transfer Slot Allocation • The purpose of this presentation is to show the concept of : • how Interconnect Migration Transfer Slots will be progressed forwards from the issue of the High Level SAN • how Interconnect Migration Transfer Slots will be allocated and managed on a CP basis within each month

4. CP Interconnect architecture pre-migration In this example : CP 'A' has 3 routes to the closing BT DLE from 2 switches in their network BT DLE L/XXX/UC CP 'A' SWITCH 1 YY/AAA/1 route 1 route 2 CP 'A' SWITCH 2 ZZ/AAA/2 route 3 BT NGS L/ABC

5. CP Interconnect architecture post-migration CP 'A' now has 3 routes to the target NGS from 2 switches in their network BT DLE L/XXX/UC CP 'A' SWITCH 1 YY/AAA/1 route 1 route 2 CP 'A' SWITCH 2 ZZ/AAA/2 route 3 transfers to take place at a pre agreed date and time BT NGS L/ABC

6. CP Interconnect route migration schedule CP Interconnect Migration Timeline Phases Admin Phase Preparation Phase Transfer Phase Stability Phase Network Freeze DLE To MSAN Tranche X M1 (-6) M2 (-5) M3 (-4) M4 (-3) M5 (-2) M6 (-1) DLE C/O M1 (-6) M2 (-5) M3 (-4) M4 (-3) M5 (-2) M6 (-1) DLE C/O M1 (-6) M2 (-5) M3 (-4) M4 (-3) M5 (-2) M6 (-1) DLE C/O Tranche Y M1 (-6) M2 (-5) M3 (-4) M4 (-3) M5 (-2) M6 (-1) Administration & Preparation Phases M1 (-6) M2 (-5) M3 (-4) M4 (-3) M5 (-2) M1 (-6) M2 (-5) M3 (-4) M4 (-3) M1 (-6) M2 (-5) In the SAN Tranche programme Transfer Phases will overlap It is important to aim to achieve the DLE to NGS CP migrations in 'M1' of each DLE to MSAN's timeline - else a build up of work will occur M3 (-4) DLE To NGS Transfer Months M4 (-3) M5 (-2) Stability Months M6 (-1) Freeze Month DLE C/O DLE to MSAN transfer Month

7. CP Interconnect route migration - detail CP Interconnect Migration Timeline Phases Admin Phase Preparation Phase Transfer Phase Stability Phase Network Freeze DLE To MSAN HLSAN (3 month transfer window) DSAN (1 week transfer window) ACOs Orders Negotiations Administration Phase Preparation Phase Transfer Phase Transfer Date RFT # Achieved # RFTs (Ready For Test) will be achieved throughout the Preparation Phase RFTs, on a per route basis, will be notified weekly to CPs by e-mail E-mail will contain the Transfer Date within the Transfer Phase - positive response required

8. CP Interconnect route transfer slot allocation HLSAN Tranche X 3 month transfer window given & agreed M1 (-6) M2 (-5) M3 (-4) W1 W2 W3 W4 W5 W6 W7 W8 W9 W10 W11 WN M1 (-6) M2 (-5) Admin Phase W1 W2 W3 W4 W5 W6 W7 W8 M1 (-6) W1 W2 W3 W4 DSAN each week 1 week transfer window given & agreed D1 D2 D3 D4 D5 the total number of working days will vary for each Tranche 1 slot gives ~ 5 x 4 x 3 = 60 + 2, non pre allocated, 'mop up' slots gives ~ + 120 At Route RFT Achieved S1 actual slot date given & agreed S2 Prep Phase Pre Transfer S3 actual time agreed S4 6 slots gives ~ 5 x 4 x 3 = 360 S5 1 slot = 0700 to 1900 - Monday to Friday 1 slot = one (minimum) ITO 1 slot = 1 DLE to 1 CP Switch S6 each extra slot gives ~ + 60 SN

9. CP Interconnect architecture pre-migration:Transfer slot allocation detail In this example : CP 'A' has 3 routes to the closing BT DLE from 2 switches in their network BT DLE L/XXX/UC CP A SWITCH 1 YY/AAA/1 route 1 route 2 could use the same signalling link(s) Slot 1 CP A SWITCH 2 ZZ/AAA/2 route 3 BT NGS L/ABC Slot 2

10. W 1 W 2 W 3 W 4 'mop-up' slots CP Transfer Slot Allocation – BT approach CP 1 Requires 22 slots CP 2 Requires 15 slots Example Allocation CP 3 Requires 12 slots • Variable number of DLEs and variable number of impacted CP Routes per migration Tranche CP 4 Requires 7 slots CP 5 Requires 7 slots • Variable number of slots required per CP per Tranche CP 6 Requires 5 slots • Variable number of slots available per Tranche CP 7 Requires 4 slots • Slots will be allocated from the beginning of the month starting with CP who has the greatest requirement that month • DLEs are then mapped over slots 15 rules developed to achieve best fit allocations per month CP 8 Requires 4 slots CP 9 Requires 1 slots CP 10 Requires 1 slots

11. 21CN CP Interconnect Migration :DLE To NGS High Level Fallback The purpose of this presentation is to show the concept of how, at a high level, DLE to NGS Fallback, if required, will be jointly managed and progressed by BT and the impacted CP.

12. 21CN CP Interconnect Migration: High Level Failures (DLE To NGS ) CP Interconnect Migration Timeline Phases Admin Phase Preparation Phase Transfer Phase Stability Phase Network Freeze DLE To MSAN Failure Failure Failure Management Escalation eg - disparity process Re-programme Transfer eg - in same Transfer Phase Fallback Administration Phase Preparation Phase Transfer Phase

13. 21CN CP Interconnect Migration: High Level Fallback (DLE To NGS) Key points in the Transfer Phase where Fallback could be triggered: • After the existing E1s at the DLE have been placed 'Out Of Service' • As new, or re-arranged, E1s at the NGS are 'Brought Into Service' or 'Returned To Service' • After new, or re-arranged, E1s at the NGS have been 'Brought Into Service' or 'Returned To Service' • Approach to Fallback: • any decision to fallback will be taken jointly between BT and the CP involved in the transfer • the decision will be based on the individual route and failure circumstances

14. 21CN CP Interconnect Migration : High Level Fallback Model (DLE to NGS) Transfer Failure Occurs Investigate Transfer Failure Fix ? Y Continue With Transfer N Fallback Required ? N any decision to fallback will be taken jointly between BT and the CP involved Y Fallback Un-Successful Instigate Fallback Fallback Successful Fix Fallback Review Reasons For Fallback Organise Failure Fix & Arrange New Date