---
title: "CPT_26_39 Specialist model assurance support"
ocid: "ocds-b5fd17-6bc5942d-7e5a-4ed2-900c-ae594f9e9562"
canonical_url: "https://d3tenders.com/contract/?ocid=ocds-b5fd17-6bc5942d-7e5a-4ed2-900c-ae594f9e9562"
markdown_url: "https://d3tenders.com/contract/ocds-b5fd17-6bc5942d-7e5a-4ed2-900c-ae594f9e9562.md"
json_url: "https://d3tenders.com/contract/ocds-b5fd17-6bc5942d-7e5a-4ed2-900c-ae594f9e9562.json"
source: "Contracts Finder"
current_stage: "Award"
buyer: "National Audit Office"
published: "2026-08-26"
---

# CPT_26_39 Specialist model assurance support

Buyer: National Audit Office  
Current stage: Award  
OCID: ocds-b5fd17-6bc5942d-7e5a-4ed2-900c-ae594f9e9562

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## Summary

The National Audit Office procured specialist model assurance support as an auditing service. The appointed supplier will oversee and lead testing of a subset of models within the National Audit Office’s model assurance portfolio. The work is delivered in the United Kingdom and concerns the assurance of models rather than general audit provision. This is relevant to firms providing independent model testing, validation, assurance leadership or related accounting and auditing services, particularly those able to manage work across a portfolio of models. The buyer is the National Audit Office, the UK public body responsible for scrutinising public spending. The requirement was classified under CPV 79210000 for accounting and auditing services.

The procurement is complete and was awarded on 1 August 2026 to Hartley McMaster Limited. It used a selective call-off from the Crown Commercial Service GCloud 14 framework. The contract value is £336,000 including VAT for the full four-year term. The initial contract runs from 4 January 2027 to 3 January 2030, with an option at the National Audit Office’s discretion to extend for up to 12 months, ending on 3 January 2031. The tender submission deadline was 1 June 2026 at 12:00 BST. The contract was awarded to one supplier, and the procurement was identified as suitable for small and medium-sized enterprises and voluntary, community and social enterprises.

This award provides a clear example of the National Audit Office’s demand for specialist model assurance through a public-sector framework. A credible future competitor would need to lead structured testing of selected models, manage assurance activity across a wider portfolio and provide evidence-based findings that an audit body can rely on. Relevant strengths include technical model validation, independent challenge, risk assessment, quality assurance and the ability to communicate testing results clearly to senior stakeholders. Firms with experience in accounting, auditing, public-sector assurance or regulated environments are likely to be well placed, as are smaller specialist consultancies able to deliver focused expert support. Familiarity with framework call-offs and the governance expected by the National Audit Office would also strengthen a supplier’s position.

## Notice

The National Audit Office awarded a contract to Hartley McMaster Limited through the Crown Commercial Services GCloud 14 framework. The supplier will oversee and lead the testing of a subset of models within the NAO model assurance portfolio. The contract will commence on Monday 4 January 2027 and run for an initial period of three years until Thursday 3 January 2030. At the NAO's discretion, the contract may be extended by up to 12 months, until Friday 3 January 2031. The estimated contract value is PS336,000 inclusive of VAT over the full four-year term.

## Key Details

| Field | Value |
| --- | --- |
| Publication source | Contracts Finder |
| Latest notice | https://www.contractsfinder.service.gov.uk/Notice/ac06dc1e-2908-4a2f-8b6b-286917e5d412 |
| Notice type | Award Notice |
| Procurement type | Framework |
| Procurement category | Services |
| Procurement method | Selective |
| Procurement method details | Call-off from a framework agreement |
| Tender suitability | SME, VCSE |
| Awardee scale | SME |
| All stages | Award |

## Dates

| Field | Value |
| --- | --- |
| Publication date | 26 Aug 2026 |
| Submission deadline | 1 Jun 2026 |
| Future notice date | Not specified |
| Award date | 1 Aug 2026 |
| Contract period | 4 Jan 2027 - 3 Jan 2031 |
| Recurrence | Not specified |

## Values

| Field | Value |
| --- | --- |
| Tender value | £336,000 |
| Lots value | Not specified |
| Awards value | £336,000 |
| Contracts value | Not specified |

## Status

| Field | Value |
| --- | --- |
| Tender status | Complete |
| Lots status | Not specified |
| Awards status | Active |
| Contracts status | Not specified |

## Buyer

| Field | Value |
| --- | --- |
| Main buyer | National Audit Office |
| Locality | LONDON |
| Postcode area | South West London |
| Postcode | SW1W 9SP |
| Country | England |
| ITL 1 | TLI London |
| ITL 2 | TLI3 Inner London - West |
| ITL 3 | TLI35 Westminster and City of London |
| Local authority | Westminster |
| Electoral ward | Pimlico North |
| Westminster constituency | Cities of London and Westminster |
| Delivery location | Not specified |

## Supplier

| Field | Value |
| --- | --- |
| Number of suppliers | 1 |
| Supplier names | Hartley McMaster Limited |

## CPV Codes

### Divisions

- 79 - Business services: law, marketing, consulting, recruitment, printing and security

### Codes

- 79210000 - Accounting and auditing services

## Release History

- 26 Aug 2026 at 13:38 - Award - Award Notice - https://www.contractsfinder.service.gov.uk/Notice/ac06dc1e-2908-4a2f-8b6b-286917e5d412

## Documents

- https://www.contractsfinder.service.gov.uk/Notice/ac06dc1e-2908-4a2f-8b6b-286917e5d412
  26th August 2026 - Awarded contract notice on Contracts Finder

## Provenance

This Markdown file is an alternate public rendering of the D3 Tenders contract record. The canonical page is https://d3tenders.com/contract/?ocid=ocds-b5fd17-6bc5942d-7e5a-4ed2-900c-ae594f9e9562. The underlying structured data is available as OCDS JSON at https://d3tenders.com/contract/ocds-b5fd17-6bc5942d-7e5a-4ed2-900c-ae594f9e9562.json.