These duration scenarios are planning assumptions, not approved dates.
Indicative modernisation delivery schedule
These are proposed low, central and high working-day scenarios, not dates, a funded plan or committed staffing. Approval and waiting time can change the actual elapsed duration.
Low scenario: 128 working days along the longest planned dependency chain.
Delivery slice
Relative working days
DSL-001 · Recover and Characterize the Executable Baseline15 days · Start
DSL-002 · Establish Measures and Approval Evidence8 days · DSL-001
DSL-003 · Resolve Identity, Relationships and Authorization20 days · DSL-001
DSL-004 · Formalize Lifecycles and Identifiers20 days · DSL-001, DSL-003
DSL-005 · Resolve Calculations and Reference Meanings30 days · DSL-001, DSL-004
DSL-006 · Introduce Modular and Durable Mutation Boundaries25 days · DSL-001, DSL-003, DSL-004
DSL-007 · Secure Files and Preserve Generated Documents18 days · DSL-001, DSL-003, DSL-006
DSL-008 · Establish Reporting and Operational Readiness18 days · DSL-001, DSL-006
DSL-009 · Rehearse Deterministic Migration, Cutover and Recovery30 days · DSL-005, DSL-007, DSL-008
Central scenario: 280 working days along the longest planned dependency chain.
Delivery slice
Relative working days
DSL-001 · Recover and Characterize the Executable Baseline30 days · Start
DSL-002 · Establish Measures and Approval Evidence18 days · DSL-001
DSL-003 · Resolve Identity, Relationships and Authorization40 days · DSL-001
DSL-004 · Formalize Lifecycles and Identifiers45 days · DSL-001, DSL-003
DSL-005 · Resolve Calculations and Reference Meanings65 days · DSL-001, DSL-004
DSL-006 · Introduce Modular and Durable Mutation Boundaries55 days · DSL-001, DSL-003, DSL-004
DSL-007 · Secure Files and Preserve Generated Documents40 days · DSL-001, DSL-003, DSL-006
DSL-008 · Establish Reporting and Operational Readiness40 days · DSL-001, DSL-006
DSL-009 · Rehearse Deterministic Migration, Cutover and Recovery70 days · DSL-005, DSL-007, DSL-008
High scenario: 575 working days along the longest planned dependency chain.
Delivery slice
Relative working days
DSL-001 · Recover and Characterize the Executable Baseline60 days · Start
DSL-002 · Establish Measures and Approval Evidence35 days · DSL-001
DSL-003 · Resolve Identity, Relationships and Authorization80 days · DSL-001
DSL-004 · Formalize Lifecycles and Identifiers90 days · DSL-001, DSL-003
DSL-005 · Resolve Calculations and Reference Meanings130 days · DSL-001, DSL-004
DSL-006 · Introduce Modular and Durable Mutation Boundaries110 days · DSL-001, DSL-003, DSL-004
DSL-007 · Secure Files and Preserve Generated Documents85 days · DSL-001, DSL-003, DSL-006
DSL-008 · Establish Reporting and Operational Readiness80 days · DSL-001, DSL-006
DSL-009 · Rehearse Deterministic Migration, Cutover and Recovery150 days · DSL-005, DSL-007, DSL-008
Dependencies and review requirements
The sequence includes access to environments, review by customer subject-matter experts, decisions about business behaviour and representative validation. These scenarios should be recalibrated after the first accepted delivery slice.
Contains public sector information licensed under the Open Government Licence v3.0. Original public repository. This independent Harten analysis was not commissioned, approved or endorsed by DEFRA or the Environment Agency.
Analysed source-archive hash is recorded; its exact upstream Git commit has not been established. The generated material does not establish complete requirements, operational security or functional equivalence.
