As research funding becomes more and more constrained and the quality of research in the UK increases, there will always be a greater number of fundable research proposals than available funding. It can be very disheartening when the research idea you have spent months developing is not ranked highly enough at Panel to receive funding. Not getting funded doesnt necessarily mean that your research isnt considered to be of high quality. You shouldnt take this decision personally; it is just the nature of research funding.
Remember that even established world-leading academics at Leeds, with significant portfolios of research grants, arent always successful.
Learn from the experience
Not being funded is a normal part of academic life and you should use each knock-back as an opportunity to learn and to develop your ideas further. To be successful, you need a degree of resilience to either re-work the project and look for another funder or develop a new project.
Now that you have sufficient distance from the application, read through your application and the call guidance notes once again in the light of referees and Panels comments and 'referee' it yourself. What would you do differently? Did your application address the priorities of the call specifically enough, or was it an obvious forced fit? Did you get the balance right between the background and what you would actually do? Did you pay enough attention to each section? Did you actually answer the questions asked in the call document? Do you understand all of criticisms that the referees had?
Another lesson that you may be able to take from the experience is about planning the application and the time it takes to prepare a high quality proposal. If you found yourself rushing the proposal and running out of time to obtain sufficient input from senior colleagues and others, then this is definitely a lesson. Next time you prepare a proposal, allow yourself more time, start earlier before the deadline, and dont put yourself in a position where you have to rush to writing. If you did plan your time well last time, remember the difference that it made. If you didnt, then your application was almost certainly not as strong as it could have been. And if your application document is not the strongest possible iteration of your research idea, your chances of getting funded are minimal.
Most UK funders do not accept uninvited resubmissions of proposals (e.g. AHRC, BBSRC, EPSRC, ESRC and MRC). These funders expect proposals to be substantially changed before submitting the same research idea as a new proposal. If your amendments only address panel and reviewer comments or make only minor changes, your proposal will count as a resubmission and be rejected. Similarly, swapping the principal and co-investigators without further alteration is judged as a resubmission.
Some other research funders do allow resubmissions (e.g. NERC), but generally you will need to declare it. While you might get lucky with a straight resubmission, experience shows that if it was unsuccessful once it will be unsuccessful again. But if you were to thoroughly revise it, take the advice of others, and resubmit, you could potentially be successful.
Submit to another Funder
Another option is resubmitting to another funder. If you do this, however, dont treat the proposal like a resubmission. Every research funder, every scheme, has different interests and priorities. As your unfunded application was written for one funder and was tailored to that particular funder a few changes will not be sufficient. The application form will probably be different and the size of the academic case is likely to be very different and hence you need to re-tailor your proposal.
You can search for other potential funding sources using Research Professional, which is a great resource.
If on reflection you decide to shelve the proposal (perhaps reviewers pointed out that the idea itself was flawed or the proposal didnt even get sent to Panel) - there really is no shame in walking away. Onwards and upwards to the next idea. Let this one go (maybe just for now), and work on something fresh and exciting instead. Just remember to take on board the lessons from your last application.