extensions to fixed term contracts

Hi there,
Hope you might be able to give me some advice.
In April this year I applied for and was appointed to what was advertised as a part time weekend post. The advertisement stated hours would be discussed at interview, and did not refer to any fixed term period.
At interview with the Director and Manager I agreed to work 1 out of every 3 weekends. These were not necessarily exactly every third weekend, sometimes I would be asked to work 2 in a row and then not work again for 4 weeks, but on average 1 in 3 weekends were worked. No discussion of a fixed term period took place at interview
I began employment in June and received a written contract six weeks later. This stated that the position was a fixed term one which ended in mid september. Firstly - is it legal to impose a fixed term on employment which has already begun, when the fixed term has not been referred to in the recruiting stage?

Prior to the end of the fixed term period I was requested by the manager of the practice to undertake work beyond the expiry date of the fixed term. I duly completed this work.
Having spent a long time telelphoning and emailing the practice to ascertain when I was next required to work I have been told that they can no longer have me work weekends as the fixed term has expired. I explained that I believed that by continuing to employ me after the expiry of the fixed term period they had extended the contract.
I was advised by the manager to get in touch with HR at head office.
I have explained to HR staff that I believe that by offering (whilst still within the fixed period) work to be performed after the expiry of the fixed period, the practice has extended the initial contract, and as such our agreed terms and conditions of working 1 in 3 weekends have continued, as I have not received any notice of termination. (The contract states that the employment can be terminated by either party giving 1 months written notice).
The head office have sent me a P45 which includes the total amount I have earned (including for the weekend after the expiry of the fixed term) as 'earnings in this employment' and states the leaving date as following the last weekend worked - ie. a month after the expiry of the fixed term. I believe that this shows that they considered and treated me as an employee beyond the expiry date of the fixed term
The HR staff claim that the contract ended at the end of the fixed term in September and also claim that I was a 'casual' worker and that the company therefore has no duty to provide me with work.
I have looked at the direct.gov determinants of employment status - the advertisement was for a part time employee post, my contract states that I am an employee, I had access to company pension, was subject to company disciplinary and grievance procedures and when the company provided work I undertook it on the agreed 1 in 3 basis. No references in the contract are made to 'casual', 'freelance', 'zero hours' or similar.
Please could you tell me whether, in your opinion, the offer of additional work to be completed after the expiry of the fixed term constitutes an extension to the contract and whether you would consider me to have been employed on a part time basis or as a casual worker.
Many thanks
jimr

It would appear that there were no set hours and no fixed work pattern - it would therefore seem, based on what you have said here, that you were a casual worker on a zero hours contract, with no obligation on the emploer to offer you work. You may have agreed to work one in three weekends contractually, but this is not what you worked since the pattern of work varied and you agreed to this by working varied patterns. And you agreed to a fixed term contract by working under one. I agree that working beyond the fixed term changes the duration of the contract, but I cannot see any benefit to you in arguing this point since it gains you no employment rights whatsoever.

What are you trying to argue?

Thanks for the advice. I am trying to argue that I was a part time worker, with variation in number of hours worked each week but a minimum of 1 weekend in 3 (36 hours). I am also arguing that since the contract was extended, and no notice has been given, I am in fact stll employed by the company.

The direct gov website states that a casual worker would have a contract which refers to their working arrangement as'casual', 'zero-hours' or similar, mine did not. My contract would seem to tick most of the boxes to put me in employee category (no mention of paternity pay though). The initial advertisement of the position as part time also indicates that the company intended it to be a part time position, rather than zero hours work?
Had it been zero hours work I would have been entitled to choose not to work the agreed 1 in 3 weekends (which I consider was part of terms and conditions agreed at outset) - this would not have been acceptable to the practice as I looked after their hospitalised animals and finding another qualified person at short notice would have been difficult and expensive.
Thanks for your opinion on this

Ticking the boxes on "potted law" from Direct.gov isn't exactly going to get you anywhere.

What the type of contract is isn't relevant - you cannot argue that you are still employed by them because you are not still employed by them. They have told you that they are no longer employing you and they have sent you your P45. That is a fairly definiative termination of contract. Since you do not have 12 months employment, then you cannot claim unfiar dismissal. You are therefore arguing angels of pinheads - what kind of employee you were and what kind of contract you had is entirely by the by because your employent was terminated.

Sorry for appearing ignorant - I was trying to define the type of employee and contract because, to me, it seems logical that if the company has breached the contract by not providing contractually agreed work and adequate notice then there are grounds to make a claim for losses resulting from that.

Also how may I recoup money not paid to me for accrued holiday?

many thanks

If you are owed holiday pay then you must send the employer a letter before action telling them what they owe and the fact that you intend to make a legal claim unless the debt is paid within a reasonable period - usually 28 days is the term. If you are then less than three months from the termination date you can make a tribunal claim, otherwise you must go through the small claims court.

If you could prove that the employer breached the notice period then you could possibly make a claim, but I think you are going to struggle. Regardless of what the written documents say, the work pattern did not seem to mirror those documents. You have said yourself that the work pattern was erractic and that you worked as and when required, and you did so for long enough to establish the practice rather than the paperwork as the applicable contractual terms. You were paid for the work you did, not according to a set working pattern or number of hours per week / month. Such an arrangement is by its nature casual or zero-hours, and I cannot see that they were obliged under the contractual terms to offer you any work on these terms. No matter what the papers say, you agreed to a variation by custom and practice. But you said that you wanted to prove that you are still in employment - and you certainly aren't.

Thank you for your explanation and for responding so promptly
best wishes jimr