NIHR i4i Funding Explained: FAST, Connect, PDA and THRIVE Compared

NIHR's Invention for Innovation (i4i) programme funds medical devices, in vitro diagnostics and digital health technologies through four distinctly shaped schemes: FAST, Connect, Product Development Awards (PDA) and THRIVE. They differ on technology readiness level, funding size, duration and, critically, on who is even allowed to apply. Picking the wrong one costs weeks of application effort on a call your company was never eligible for.

What i4i is and who runs it

i4i is a National Institute for Health and Care Research (NIHR) programme that funds translational research into medical devices, in vitro diagnostic devices and digital health technologies addressing an existing or emerging health or social care need. It sits alongside Innovate UK and SBRI Healthcare as one of the main public funding routes for UK health innovators, but it is run to NIHR's own rules, not Innovate UK's, and those rules vary again between i4i's own schemes.

The programme is aimed at applicants who already have proof-of-concept evidence, not early-stage ideas. Every i4i scheme expects some demonstration that the underlying technology works before it will fund the next stage of development.

FAST vs Connect vs PDA vs THRIVE: eligibility, TRL and funding size

Here is how the four schemes compared as of September 2026, based on NIHR's own published guidance for each stream:

FAST (Funding At the Speed of Translation) is the fastest route: awards of £50,000 to £100,000 over 6 to 12 months, with a minimum TRL 5 requirement, meaning the technology must already function with prior feasibility or pilot data. Eligible lead organisations include higher education institutions, SMEs, NHS or social care providers, not-for-profits, and local authorities.

Connect is i4i's SME-focused researcher-led stream, funding £50,000 to £150,000 over 6 to 12 months. The lead organisation must be UK-registered, with no more than 250 staff and turnover under €50 million, and must be on Companies House before applying. Unlike FAST, Connect does not require a fixed TRL entry point beyond proof-of-concept evidence, and unlike PDA it does not require a formal collaborator, though NIHR encourages one. Connect runs roughly once a year; the most recent confirmed round opened in February 2025, and NIHR had not published a 2026 Connect call date at the time of writing, so check NIHR's live funding opportunities page before assuming a round is open.

PDA (Product Development Award) is the largest and longest scheme: funding is uncapped, though NIHR notes that applications below £500,000 are rarely competitive, and typical awards run £0.5 million to £1.5 million. PDA uses a two-stage process, an outline application followed by an invited full application, and requires a genuinely collaborative consortium with at least one co-applicant from an organisation other than the lead. An SME can lead a PDA bid, but not alone.

THRIVE (Translate Healthcare Research through InnoVation and Entrepreneurship) is different in kind, not just size. It funds up to £150,000 over 9 months alongside a structured programme of entrepreneurial training, mentoring and peer support, aimed at early-stage innovations that tackle health inequalities. Eligible applicants are academic and clinical entrepreneurs, research institutes, NHS providers, charities and community interest companies.

Why SMEs are excluded from THRIVE

This is the detail that catches companies out, because THRIVE reads on the surface like the friendliest entry point: a smaller award, a 9-month timeline, and mentoring built in. It is not open to your company if you are a registered SME. THRIVE is designed to take an academic or clinician with an early-stage idea and give them the entrepreneurial scaffolding to found a company around it, not to fund a company that already exists. If your business is already incorporated and trading, THRIVE is not your route regardless of how well your technology fits the health-inequalities remit; Connect or FAST is the equivalent entry point for an existing SME at a comparable stage.

Choosing the right scheme for your stage

In practice, the choice usually comes down to three questions. First, are you an SME or a pre-company academic team? If the latter, THRIVE is worth a serious look; if the former, it is not an option. Second, what TRL is your technology genuinely at, with evidence to back it, not aspiration? FAST needs TRL 5 and functioning data; Connect and PDA will take proof-of-concept-stage work. Third, can you resource a genuine multi-organisation consortium, and do you need seven figures rather than six? If yes to both, PDA is the scheme built for that; if you need a faster, smaller award and can go it alone, Connect fits better.

A company that is TRL 4, incorporated, and working solo should be looking at Connect, not stretching a FAST application past its TRL floor or trying to assemble a consortium it doesn't need for PDA. Matching the scheme to the true stage of the technology, not the scheme with the biggest headline number, is most of what decides whether an i4i application is worth the weeks it takes to write.

2026 call dates

FAST's April 2026 round and THRIVE's March 2026 round have both now closed to new applications; outline applications for THRIVE March 2026 closed on 17 April 2026, and FAST's April 2026 round closed on 29 April 2026. The next confirmed opportunity is PDA, which NIHR has scheduled to open on 7 October 2026, with outline applications due by 1pm on 2 December 2026. If your project fits PDA's TRL and consortium requirements, that is the live near-term target. Connect's next round had not been dated as of this writing; NIHR's funding opportunities page is the place to check before building a timeline around it.

How GrantHero helps you apply to the right one

Getting the scheme choice right before you start writing saves the most time of anything in this process. GrantHero's discovery matching checks your company's stage, structure and evidence base against live funding competitions, including i4i, so you're not weeks into a THRIVE application before discovering the SME eligibility rule, or building a PDA-scale consortium for a project that Connect would fund faster. Where a competition is genuinely worth pursuing, our platform combined with experienced grant experts helps you draft and review the application itself, rather than leaving you to interpret NIHR's guidance alone. See current plans on our pricing page, and browse our healthcare sector page for how this fits alongside other health-focused funders. If you're not yet sure what technology readiness level your project is actually at, our guide to technology readiness levels is the place to start before you pick a scheme.

And if none of the four fit right now, that's worth knowing before you spend the time, not after a rejected outline application. An i4i scheme aimed at a stage your technology hasn't reached yet is not a competition worth entering this round.