ADVICE OF BORROWING TERMS                    Ref: CM  RM03



BRANCH/UNIT:      National Westminster Bank PLC
                  4th Floor, Society Building,
                  176 London Road, Portsmouth, PO2 9DR


DATE:   27 March 1998


BORROWER'S NAME:   VICON INDUSTRIES (UK) LIMITED (Registered Number 1551194)
                    Brunel Way, Fareham, Hants   PO15 5TX


(This letter replaces the Advice of Borrowing Terms letter dated 22 April 1997)


Subject to the Bank's  rights  below and subject to the Bank's  rights under the
`General terms upon which the Bank makes facilities available', it is the Bank's
current  intention  that the  facilities  specified in this `Advice of Borrowing
Terms'  (except for those  facilities  which are  subject to their own  separate
facility  documentation  covered  below  under  `Facilities  subject to separate
documentation') should remain available until 27 March 1999.




FACILITY 1:


Facility Type: Overdraft.


Amount:   (pound)600,000  (Six hundred thousand pounds).


Purpose:   Working capital requirements.


Repayment:   Fully fluctuating.


1st Debit Interest Rate:   2% per annum above NatWest's Base Rate from time to 
                           time.


2nd Debit Interest Rate: (Applicable above(pound)600,000)  5% per annum above 
                         NatWest's Base Rate.


Payable:    Quarterly.




REPAYMENT:


It is the Bank's current intention that the facilities should be reviewed by the
dates indicated herein.  However,  all amounts  outstanding under the facilities
are repayable on demand, which may be made by the Bank at its sole discretion at
any time.  The  facilities  may also, by notice,  be withdrawn,  reduced or made
subject to further conditions or otherwise varied.

INTEREST:

All rates specified above are variable.  If the interest rate specified above is
not linked to the Bank's Base Rate,  interest  will be charged  initially at the
rate per annum specified  above,  which may vary from time to time at the Bank's
absolute discretion.  Details of the current rates are available from the branch
or office where the facility is provided.

Interest on any  indebtedness  from time to time in excess of agreed  facilities
will be charged  at the  interest  rate  detailed  above.  An excess fee will be
charged at the Bank's  published rate from time to time  (currently  (pound)3.50
per day) for each day that your agreed overdraft limit is exceeded . The Bank is
not obliged to allow (or to continue to allow) any such excess borrowing.

The Bank may alter the basis upon which  interest is calculated  (including  the
size of the margin charged over the Bank's Base Rate or other published rate) on
facilities  and/or the amount of any regular  repayments of facilities which are
repayable  on demand (or by notice),  but it will give the  customer one month's
notice before doing so.


OTHER FACILITIES:

Facility Type:   Forward Exchange Liability.

Amount:   (pound)200,000 (represents 10% of contract).



Facility Type:   Terminable Indemnities (T/I).

Amount:   (pound)200,000.

Purpose:   HM Customs & Excise Duty Deferment Bond.



Facility Type:   Inward Collections - Documents Release in Trust

Amount:   (pound)20,000.

These facilities may by notice be withdrawn,  reduced or made subject to further
conditions or otherwise varied.




SECURITY:


The Bank  continues to rely on its existing  security (and  requires  additional
security  where  specified)  detailed  below for the  discharge on demand of all
present and future  liabilities  (both actual and contingent) of the Borrower(s)
to the Bank.  The  liabilities  secured will  include  without  limitation,  all
liabilities,  of the  Borrower  to the Bank  under the  facility  or  facilities
specified in this Advice of  Borrowing  Terms  including  those which are listed
below under the heading `Facilities subject to separate documentation'.

From time to time the Bank may wish to revalue the  security and the cost of any
valuations required by the Bank will be met by the Borrower. Further information
is  included  in the  `General  terms  upon  which  the  Bank  makes  facilities
available'.


Date Executed/New    Title of Security            Asset
- ------------------   --------------------------   ------------------------------
6 July 1989          Guarantee(pound)1,000,000    Given by Vicon Industries Inc.

17 October 1990      Mortgage Debenture           Capturing all assets of the 
                                                  company.

9 April 1997         First Legal Mortgage         Site P3, Brunel Way, 
                                                  Segensworth Industrial Estate,
                                                  Fareham.


FEES:


Type:    Overdraft renewal fee.

Amount:  (pound)1,850  (from account 01144642  560064).

Date to be debited:  15 April 1998  (last annual fee was paid on 27 March 1997).


OTHER CONDITIONS:

    Please  continue to provide  monthly  management  accounts in the  existing
    format, together with aged debtor profile.

    Lending  formulae to continue  whereby:  1) Debtors  less than 90 days plus
    stock (minus  preferentials)  to cover  overdraft by 250%,  2) Debtors alone
    less than 90 days to provide 150% cover of overdraft.


FACILITIES SUBJECT TO SEPARATE DOCUMENTATION

Facility Type:   Commercial Fixed Rate Loan

Amount:   Balance(pound)454,167 plus interest (Originally(pound)500,000  
          drawndown 14 April 1997)




GENERAL TERMS:


Please note that all  facilities  specified in this `Advice of Borrowing  Terms'
are made  available  subject  to the  `General  terms  upon which the Bank makes
facilities   available',   except  for  those   subject  to  separate   facility
letters/agreement  forms which do not expressly  incorporate  the General Terms.
Please  note that all  facilities  are also  subject  to any terms  which may be
implied by English Law.






John McLellan
Corporate Manager


The Borrower confirms acceptance of the above terms and conditions pursuant to a

                                                  30 - 3 - 98
Resolution of the Board of Directors on .......................................




                                            Chris Wall
BORROWER'S SIGNATURE:   ......................................................
                                        For and on behalf of
                                  Vicon Industries (UK) Limited

                                         30th March 1998
               ...........................................................Date