Thank you TreeofLife.
Yes, I have had some feedback from “serious” employers. One of them stated that they wanted someone who could fight for grants and resources (both within the organisation and outside) and I am certainly not a fighter. I have always treated study/job as a hobby; I do it because I like it. I know this is a weakness and I need to work on it but the plus side is that I have always enjoyed my work, been relatively productive at it, and have had good rapport with my line manager or supervisor.
I do not have a good answer for interview questions such a strengths etc., I find the language spoken in these scenarios, particularly that used at government agencies, incomprehensible. This could be one reason for me not getting a job.
I apply for jobs that I believe that I am capable of doing not what I ought to be doing. The irony is that I tend to get responses, or even interviews, at world-class centres, such as Rutherford and Appledon Laboratory, and not even a rejection email from the others (particularly from the employment agencies).

Thank you TreeofLife for your response. I have been applying for jobs that I think that I am capable of doing, (such as lab jobs). I have not been too bothered where the job was based, how much it payed and whether it was temporary or permanent. And that is perhaps the reason why I have had so many interviews.

It is difficult to have much self confidence when you are applying for jobs and there is not even a rejection email. However, I have found out that going back to "school" to learn a new language has helped my self confidence. Similarly, learning a new skill, (swimming in my case), practicing it regularly and improving continuously has had an amazing boost to my self confidence. It proved (to me) that there was nothing wrong with me and I recommend it to anyone.

I am a British scientist living in Italy. I had moved from Afghanistan to the UK some 25 years ago. I am giving you this information not to gain sympathy vote but to inform you that by the time I went to university I was already a good few years older than my classmates and having lived in London, I have kept my foreign accent.
I have always loved science but was never good at the language of it (maths). For this reason I choose to do a chemistry degree instead of physics and even though I did not get very good grades I was lucky enough to be admitted to a PhD. My supervisor had made it known that “do as I tell you and you will get a PhD”. I did and I got a PhD. In fact I stayed on to do a postdoc but original research, I did not do. Then I moved on to “the real world” and found it very difficult to find a job. I was unemployed for 2 years (except for a couple of months temp work) but finally found a job in the research branch of an SME. There were only three of us in the “company” with limited budget and resources. The notion of specialist had gone out of the window. I was (quite rightly) expected to do everything and I did. For this reason, my line manager, one of founders of the parent company, was very happy with me. Then two years ago, the other directors of the parent company had decided to close the research branch which meant that I became redundant.
For ten years I had been commuting between Italy, where my girlfriend lives, and the UK but when I lost my job there was no justification to stay in the UK when I could do my job hunting from Italy. I spent a year job-hunting which resulted in 8 interviews, all in the UK. I even managed to reach the 2nd interview on one occasion.
To miss quote Ken Dodd “it may surprise you but I am not very clever”. In fact, I am average or slightly above average except in Math and reading which I am useless. I think I am dyslexic but have never tested for it (as they say only posh people are dyslexic for the rest it is called stupid). I know that I am not intelligent enough to be an academic running my own group or a project leader in industry but I am certain that I can do controlled scientific experiments, collect data, analyse the data and write reports. I am baffled why I cannot find a job that requires these skills.
It is a year that I am learning Italian and making good progress but still no job. I do not enjoy job-hunting and being a student again was a welcome relief. I know that this cannot continue, especially now that I am 40.
Learning Italian has removed my prejudice about Italy and Italians. I quite like living here now and would like to remain here. It is the small matter of finding a job. I am not too fussed about what kind of job but having worked/studied science all my life, I still believe that I have a better chance to find science job than any other.
Any comment or advice is welcomed.
Thanks