Google looks increasingly at risk of breaking its pledge to keep DeepMind independent from the rest of the business, as a Telegraph investigation finds almost a fifth of the artificial intelligence arm’s staff have been moved in from other Google divisions.

London-based artificial intelligence company DeepMind is one of Britain’s most successful technology firms of the last decade. It owns an AI-powered app called Stream that uses NHS patient data to help doctors diagnose and detect illnesses. However, Google’s increasing involvement with the firm has raised questions over the privacy of patient data used by the app.

Research compiled by The Daily Telegraph found around 18pc of current DeepMind employees had worked within other Google businesses, including in its driverless car arm Waymo and its artificial intelligence research team Google Brain.

According to data from LinkedIn and not provided by DeepMind, of those employees, 95pc had moved directly from one part of Google to the DeepMind team, and had held roles ranging from research engineers to strategy-focused posts.

The only places where a larger portion of staff had come from were academic institutions.

The Daily Telegraph understands the DeepMind interview process is the same for all potential candidates, irrespective of whether they already work for Google.

The findings come amid recent reports that there has been a blurring of lines between DeepMind and the rest of Google.

When Google bought DeepMind, back in 2014, it put in place a number of mechanisms to keep the company separate, setting up an independent ethics board to review the use of DeepMind’s technology and preventing Google staff from entering the DeepMind levels of the London headquarters.

In the 2015 Google restructure, DeepMind became part of the Alphabet holding company, splitting it out from Google, in a move many saw as an effort to ensure its independence.

However, recent signs have suggested Google is starting to encroach on DeepMind’s autonomy and the latest earnings for DeepMind showed the majority of its revenues were coming from selling its software to Google.

A spokesman for DeepMind said: “DeepMind is a separate team that operates autonomously within the Alphabet group but we collaborate a lot with many groups at Google."

Just over two weeks ago, DeepMind announced Google was taking control of its healthcare division, moving it under the Google Health umbrella instead.

Some had raised concerns over what this meant for the patient data being processed by DeepMind, which holds contracts with the NHS, although DeepMind has said patient data would continue to be kept strictly separate from other Google projects and products, and that data processing remained subject to data protection legislation.